efan problem

[BOSS]

Hi,


I'm having trouble with the fans after installing the harness...I've gone over and over my install and can't seem to find my problem.

So what happens is the pass side fan comes on when the key is turn to run position..and thats it. Then the truck overheats after running a few minutes.

The driver side fan never comes on, and I suspect the pass side fan is only on a low setting. The pass side fan remains running for 5-8 seconds after I stop the truck.

I triple checked that blue pin 42 was in the correct blue plug,.

I tap'd the "AC tap wire" into the lime green wire on the loom running verticle alongside the alt bracket. The "AC tap wire" color does not match the dark green wire in the compressor plug...is that an issue?

Any ideas?

[Justin]

What you are encountering is the green A/C tap seeing power 100% of the time.

When the A/C tap is powered alone, you will have one fan on high.
When the PCM tap is grounded alone, you will have two fans on low.
When both taps are active, you will have both fans on high.

Sounds to me like the PCM tap is either not inserted properly or is in the wrong pin hole (hence only one fan is coming on). Did you remove the acryllic blue pin cover before pushing the pin through?

From what you're describing, the A/C tap is not matched up to the correct wire either. That single fan should kick on ONLY when the A/C compressor is active. Look for another very similar wire in the loom to tap into.

[BOSS]

Ok I think thats one problem, the green wire to the compressor is actually hunter green...i tap'd the same color from your harness as you suggested ealier, which was lime green loom and lime green harness.

I don't think i removed that blue acrylic cover, but I can see where my pin was pushed through, I actually did it twice because it wouldnt go 100% the length of the hole the first time..it was only sitting at 80% through and it wouldnt budge. I finally got it all the way through...im telln ya its #42 if my name is bobby LOL

B

[BOSS]

If you look on blizz's how-to, I removed that grey plastic cover which covered the back of the pins...is that what you're talking about? you cant push the pin into the plug without removing that.
b

[Justin]

If you look on blizz's how-to, I removed that grey plastick cover which covered the back of the pins...is that what you're talking about? you cant push the pin into the plug without removing that.
b

That has to be removed but so does the blue cover on the other side. The pin will not seat without the cover being removed. Check your hotmail account.

---------- Post added at 12:05 AM ---------- Previous post was at 12:04 AM ----------

Ok I think thats one problem, the green wire to the compressor is actually hunter green...i tap'd the same color from your harness as you suggested ealier, which was lime green loom and lime green harness.

I don't think i removed that blue acrylic cover, but I can see where my pin was pushed through, I actually did it twice because it wouldnt go 100% the length of the hole the first time..it was only sitting at 80% through and it wouldnt budge. I finally got it all the way through...im telln ya its #42 if my name is bobby LOL

B

It wouldn't be the first time that a wire wasn't quite the color it was supposed to be...

[BOSS]

Will do Justin, I'll check my mail in a bit... I'm a little dumbfounded as to why the blue cover needs to be removed because my pin pushed all the way through, and when I pulled it out it was still flush with the other pin lengths...thats an easy fix if that's the problem

B

[BOSS]

Thanks btw, see you in july...truck is a different entity altogether since last time you were here
B

[BOSS]

Ok I see the pics, thanks....glad to know they exist :)

So I did everything good (including punching through the yellow rubber pin cover with my needle pick tool) EXCEPT remove that blue acrylic cover. I will check that out tomorrow and rework the AC clutch wire.

Thanks again
B

[Justin]

Will do Justin, I'll check my mail in a bit... I'm a little dumbfounded as to why the blue cover needs to be removed because my pin pushed all the way through, and when I pulled it out it was still flush with the other pin lengths...thats an easy fix if that's the problem

B

I can almost guarantee that is the problem as the cover prevents the latching portion of the pin "tray" from allowing the pin to retreat. In the same token, it cannot move far enough for the pin to clear this latch and fully seat.

[My01yuk]

How beneficial are these E-fans.

[BOSS]

How beneficial are these E-fans.

I already noticed an increase in throttle response. Basically that engine driven fan puts a drag on the crank, because the crank is what spins it.

Not only that, but at engine idle, the crank-driven fan can't cool the vehicle OR the a/c as well because it can't spin as fast.

So those are benefits enough to me, plus I like having all that room in my engine bay freed up and the loud ass crank driven fan gone...mine was LOUD, Justin said it was the loudest he'd ever heard LOL

B

[Rivieraracing]

Hey boss, were the fans you bought OEM used ones or are they OEM fit new ones? Also, did you ever get the tranny cooler and fan yet, I'm about to order my fan!!

[onedeadpresident]

Dark green wire is hot when the key comes on. The light green is active when the ac is engaged. Made the same mistake. :beer: I only have one of mine working and my mine won't overheat using one. It was 98 here today. ???

[My01yuk]

Cool, how much are they and do you have to get two?

[BOSS]

Ok after getting the pics from Justin and rechecking:

AC Compressor wire
, it looks like my compressor wiring is definitely a different color green again. I'm going to pull the connector out of the compressor and tap right off that so this issue is gone.

PCM #42 PIN
I pulled the blue acrylic cover to make sure the #42 blue pin gets installed correctly inside that acrylic adapter. I checked and checked, and checked again that when the acrylic cover gets put back on, the pin does not move either up or down ...same as others. I also made sure the pin that the #42 PIN plugs over is not bent and neither are any of the other pins.

Also, if I turn the AC off...no fans EVER come on but the truck does NOT overheat. :nono:

I'm convinced that one of two things is happening:
1) these radiators are really efficient
2) my #42 PIN is not active

Bobby

[BOSS]

Dark green wire is hot when the key comes on. The light green is active when the ac is engaged. Made the same mistake. :beer: I only have one of mine working and my mine won't overheat using one. It was 98 here today. ???

Ok so what's the deal with this harness? Aren't both fans supposed to come on individually for something, together for something, low for something and high for another?


B

[BOSS]

Also, the green wire is supposed to go to the AC clutch wire...so when the clutch comes on the fan comes on, correct?

B

[BOSS]

Ok so now I'm frustrated..this is getting really really old

B

[JennaBear]

Are your fans used? Did you bend any of the PINs?

---------- Post added at 11:51 PM ---------- Previous post was at 11:33 PM ----------

What you are encountering is the green A/C tap seeing power 100% of the time.

When the A/C tap is powered alone, you will have one fan on high.
When the PCM tap is grounded alone, you will have two fans on low.
When both taps are active, you will have both fans on high.

Sounds to me like the PCM tap is either not inserted properly or is in the wrong pin hole (hence only one fan is coming on). Did you remove the acryllic blue pin cover before pushing the pin through?

From what you're describing, the A/C tap is not matched up to the correct wire either. That single fan should kick on ONLY when the A/C compressor is active. Look for another very similar wire in the loom to tap into.

This is how it works...


A real easy way to test the fans, is to touch the green wire to power, and the blue to ground and that will turn both on high.

[BOSS]

Are your fans used? Did you bend any of the PINs?

Fans are brand new, and no bent pins anywhere.



This is how it works...

A real easy way to test the fans, is to touch the green wire to power, and the blue to ground and that will turn both on high.

I'm gunna give it a shot again tomorrow, I'm really frustrated..when I started it admittedly I knew nothing bout what I was doing as you can tell by my posts, but I believe I do understand now.

Thanks for your continued support.

B

[BOSS]

Tested the fans, both come on which is great :)

AC fan
I tap'd the AC to the correct wire and it works with the clutch, which unfortunately for me was the first wire I had tap'd so I was right all along...the wires change color due to 10yrs of heat I guess.

PCM #42 pin
To test this, I had to drain half the coolant and drive down the road with the AC off. That got the coolant hot enough to turn on the fan, then turned on the AC and woahla, both worked.

Thanks for your support, I see a TYF how-to post coming up. In your stickie section maybe? It's your section, LMK.



B

[JennaBear]

Glad you got it figured out! My next question was gonna be how hot you were letting the engine get for the fans to turn on :P.

Whereever you would like to post up the sticky is fine with me.

[BOSS]

My next question was gonna be how hot you were letting the engine get for the fans to turn on

when it crept over 200 i coasted her to a stop ;-)

Can the temp setting be lowered in the pcm code when I get ASC? I've read the debates ;-)

B

[JennaBear]

Yes the temps can be lowered, but it does affect the effectiveness of the fans.

---------- Post added at 08:56 AM ---------- Previous post was at 08:54 AM ----------

Shoot Justin an email to discuss further.

[bottomline2000]

I got a question on this. I got my fans installed. They both seem to run on low all the time while the truck is running. they don't come on with just ignition. made that mistake and fixed it! Both fans cycle to high once the a/c is turned on. Is this normal operation since I have the 42 pin connection with the a/c wire tap? are they supposed to both be fully off at any time?

[JennaBear]

Both fans low- PCM trigger
Both fans high- A/C and PCM trigger
One fan high- A/C

[bottomline2000]

Both fans low- PCM trigger
Both fans high- A/C and PCM trigger
One fan high- A/C

so does this mean something is wrong with my pcm trigger since the fans are on low even on first start up when the truck is cold? my pcm trigger is not cycling on and off.

[JennaBear]

Check your wiring and make sure the wires aren't touching anything else.

[bottomline2000]

I'm at a loss. I pulled everything out and even checked the wire loom. same problem. I actually started the truck with no a/c wire tap and same thing. both fans come on low. The pcm tap is solid, no bent pins or anything, pin fully seated and all. No where for wires to touch. could a bad relay cause this problem?

[JennaBear]

No that would not be a bad relay, as they wouldn't work at all. It is either that the wire is grounded out somewhere, or your A/C pressure sensor is showing high pressure. If you would like, we can disable the A/C trigger inside the PCM to rule that out. Shoot us an email if you would like to go that route (tuning@blackbearperformance.com).

[bottomline2000]

It has to be the pin wire grounding out somewhere. I don't think its the a/c pressure sensor since both fans cycle on low. I would think a high reading on a/c would mean one fan would cycle on low constantly IIRC. They do cycle to high if I turn the a/c on which they are supposed to do if the truck is at op temp, but the PCM seems to not know when to activate the fans based on engine temp. If the signal from the pcm activated the fans based on engine temp then everything would work as expected. I'm pulling the computer again and checking the pin connection to see if anything could possibly be grounding there.

Thanks for the help Jenna. I'm going to figure this out.

[bottomline2000]

well I pulled the computer and checked. Nothing outta order. anyone have a diagram of the efan wiring harness? Also, I think I'm gonna have to have an electrician of mine check this out. getting very old. soon as my stupid post count is high enough maybe I can buy a new harness and try that since I've seen a few for sale. I want this problem gone!!

[Justin]

All of the harnesses are bench tested before arriving to us here for sale. I really think that it is the A/C pressure signal being sent to the PCM. I've seen one other situation in the past where a 2000 was showing the voltage equivalent of 500psi at the PCM all of the time. 210psi is the trigger for the fans to activate.

[bottomline2000]

Justin I sent you an email on this. How can the signal be disabled and how would this affect the a/c operation? I knew I should have had everything ready at the tune, its' just my luck I'm the exception.

[JennaBear]

We would just remove the A/C pressure fan condition. This would not affect the A/C use at all.

[bottomline2000]

ok, let me know the next steps so we can remove the fan pressure condition. I'd imagine this involves sending my PCM to you.

[JennaBear]

Justin will get back to you on your email.

[bottomline2000]

I sent Justin an email. I have found the problem.

[bottomline2000]

well I take that back. The relay sounded like it had rocks in it. I replaced it and still have the constant fan on condition. Problem remains....

[JennaBear]

This is with the new PCM in? So it stopped momentarily?

[bottomline2000]

I have the new PCM in and they still cycled low. I removed a relay and it sounded like something was loose inside. I tapped on it and the fans cut off, but did not cycle back on based on engine temp. the one fan did come on when I turned on the a/c though. I replaced the relay with a new one and even swapped them around and they still will not cycle on and off. They stay on low until I turn on the a/c then cycle to high. pcm doesn't seem to know what the engine temp is so it defaults to keeping them on. no CEL or anything. weird...

[bottomline2000]

anyone got any ideas on what may be causing my fan problem? I think the fans both cycled to high today. before it sounded like they were both going high with the a/c, but I think it may have only been the one fan for the a/c. I let it sit running in 100 deg heat today and all of a sudden I get a big amp draw and the fans really sucked a lot of heat out the radiator and someone standing next to my truck backed up since it was blowing so hard. my temp gauge dropped so it seems they are trying to work. still won't turn off completely.

luckily its hot as hell in TX right now and the constant running of the fans is not a problem. I'm getting 15mpg even with the a/c blowing so the truck is running good.

Jenna, the PCM should be there in the next couple of days. if you got any suggestions let me know.

[Justin]

anyone got any ideas on what may be causing my fan problem? I think the fans both cycled to high today. before it sounded like they were both going high with the a/c, but I think it may have only been the one fan for the a/c. I let it sit running in 100 deg heat today and all of a sudden I get a big amp draw and the fans really sucked a lot of heat out the radiator and someone standing next to my truck backed up since it was blowing so hard. my temp gauge dropped so it seems they are trying to work. still won't turn off completely.

luckily its hot as hell in TX right now and the constant running of the fans is not a problem. I'm getting 15mpg even with the a/c blowing so the truck is running good.

Jenna, the PCM should be there in the next couple of days. if you got any suggestions let me know.

You should be able to determine if just one fan or both are running by looking at them with the engine running. Standing beside the driver's side fender with the hood popped should give you enough of a vantage point to see.

Justin

[bottomline2000]

yeah, I'm sure they are both running. Today was the first time I noticed the amp draw and the fans pulling a lot more air so they both must have cycled to high. maybe my thermostat is jacked up and its stuck in open loop.

[bottomline2000]

regardless of this small problem with the fans I could not be happier to have them today.. 107 in Dallas and my truck was loving life!! Damn it was nice to drive around without the roar of that clutch fan and feeling of pulling a large parachute and worrying about overheating all while freezing my butt off lol...

blackbear tune had me plowing through traffic in comfort. Thanks for all the help on this Justin..

[bottomline2000]

I'm bumping this back up since I still have the same problem. My blackbear harness was starting to melt at the relay so I decided to go ahead and get another one. I still have the constant on of both fans. I went with a Nelson harness this time and be damned if nothing has changed. I run my power wire directly to the battery from the alternator bypassing the junction box, but the fans get their power from the junction box by way of the pos wire from the battery to the junction box I seem to be the only one having this problem. Could this be causing my problem? I'm sure other people are bypassing the box.

I've done this install so many times its ridiculous. I would like to move on to getting my suspension work done, but this is irritating the hell out of me. any ideas would be greatly appreciated.

[Rivieraracing]

Are you sure you are using the correct A/C wire, the green one? There were 3 wires in the truck harness that looked like they would be the right color but all 3 had different characteristics to what they did to the fans! One didn't let the fans come on at all, one had the fans come on all the time no matter what, and the last one I found and tried that actually looked to be the correct one color wise made them work correctly!!

[bottomline2000]

Yeah I actually went thru the same thing when I first installed the harness. I'm sure I have the right wire tapped and I even traced the wire back to the compressor. I can disconnect the a/c tap and the fans do the same thing, both cycle low. I turn the a
a/c on and they cycle high. I'm going to a wire from the alt to the junction box and see if this fixes the problem. Justin from blackbear even sent me a new PCM to remove some potential problems and I still have this issue. I only have one spot open around pin 42 so I couldn't tap the wrong pin if I wanted. I don't have any check engine codes or anything so the only thing left is the power supply.

[JennaBear]

Gianni, shoot Justin an email, maybe we can change your operating system.

[bottomline2000]

Wow, thanks Jenna. Will do. I just changed the thermostat, changed the belts and flushed the coolant all for the sake of these fans so a few things to rule out. Riviera I want to say I did my wire tap based on some pics you posted now that i think about it.

[bottomline2000]

ok, after much exhausting research I seem to have found my problem. There is a posting on performance trucks that describes my condition exactly. It seems to be something that only affects 2000-2001 trucks and may be something to do with the OS.

Jenna/Justin-take a look and tell me what you think. I don't know if this can be done or not. What's a 1mb PCM and can I upgrade? These guys were using HPT so I don't know how that varies from Efi Live, but it describes my condition exactly.

http://www.performancetrucks.net/forums/showthread.php?t=465926&highlight=efan+running

[JennaBear]

Yep, we were going to try to do that for you, as per my previous post.

[bottomline2000]

Ok. I sent an email to Justin earlier.

[bottomline2000]

Jenna, I got my new PCM. How do I perform the crank relearn? Is there a code reader I can buy to do this? truck won't start so I'm lost as far as having a dealer or shop perform this.

---------- Post added at 08:55 PM ---------- Previous post was at 08:35 PM ----------

nevermind. I got the crank relearn to work.

[waxworkz]

ok sorry to revive an older thread but i need help. i got my truck tuned this past monday and had the efan pin 42 turned on. i installed my fans, harness and i get nothing on the right side fan. seems as though the green wire is not providing enough voltage to turn on the pass side fan with the ac. i know i have the right green wire because one did nothing, one runs all the time, so last green wire has to be ac clutch. is it supposed to turn on right away with the ac? does it take time to build voltage? what is going on? also the left fan only turned on once. hasnt turned back on again. truck got up to about 200 and nada! is this normal? i know the pin is in properly, i double checked it and it worked once. if i power the green wire the right fan comes on but not the left. i have an 01 suburban with 5.3 i need help guys i need to drive my truck by tomorrow after noon and dont want to be over heating!

[Rivieraracing]

Glad it was a simple fix!! ;>)

[waxworkz]

yeah as simple as starting the car LOL

[bottomline2000]

how did you fix it? This problem still exist for me so it's not old at all.

[waxworkz]

how did you fix it? This problem still exist for me so it's not old at all.

whats your issue?

[Rivieraracing]

yeah as simple as starting the car LOL

Ha ha ha!! It's all good, sometimes in the heat of an install the simple things get overlooked!! Glad I could help ya out!!

---------- Post added at 08:07 AM ---------- Previous post was at 08:06 AM ----------

how did you fix it? This problem still exist for me so it's not old at all.

You can't get the A/C part of the fans to work either?

[bottomline2000]

actually my problem is my truck doesn't seem to know when to activate the fans. They run constantly. Not with just ignition, I made that mistake. Once I start the truck both fans run on constant low. When the a/c is turned on they both cycle to high. I have flushed the coolant twice, replaced the thermostat, the coolant temp sensor, moved the a/c wire tap to a different section of wire, tried multiple computers, replaced the wiring harness nothing seems to fix the problem!!

I've had electricians look at it and the computer is grounding the fans and since its not factory no one seems to know how to diagnos the problem.

It sucks cause initially I only wanted the tune for the fans so ironically I love the tune, but the fans don't work right. The only thing left is to buy another set of fans.

I have no clue and this little upgrade has cost me a pretty penny and is really the only reason I don't want to dump any more $$ into the truck.

[waxworkz]

are you using the factory fans? i used the factory fans off an 05 tahoe. sorry i havent read all the details of your set up. i see in your signature, it says oem fans? but oem from what vehicle??

[bottomline2000]

I have fans from an 05 Yukon with nelson harness.

[waxworkz]

is your air conditioning system working ok? only thing that i can see causing that is a bad ecm or a short somewhere.

[Rivieraracing]

Sounds like you may want to think about ditching the nelson harness and go for a Black Bear one, I'd email Jennabear on here and ask their opinion on the matter!!

[bottomline2000]

I started out with a blackbear harness. That's why I have a Nelson one now.

[bottomline2000]

is your air conditioning system working ok? only thing that i can see causing that is a bad ecm or a short somewhere.

It has to be a short somewhere. A/c works fine, but there is something up with my fans. They seem to have a big amp draw. I currently have my stock alt with the blackbear pulley on and I can overload the system if I turn the a/c on high and the fans engage. There is a big drop in my voltage gauge everytime the fans cycle to high. My stock alt is 130 amps.

I blew my big alt racing my truck one night. Didn't like the rpm lol.

I have about 1400 rms in stereo and it's just too much for the stock alt to handle even with the pully so I don't even try to crank it.

All this leads me back to where I started. I want to start with testing the fans amp load. This will be the last time I buy anything electrical from a junkyard!

I've searched all over the Internet and only found one guy on pt net that had the same problem and it turned out to be tune related fixed with a patch but he was using something other than efi live.

[Rivieraracing]

Dang, sounds like you've been through your share of problems for sure with the e-fans!! There are a few folks on here from Texas, maybe one of them would be nice enough to chime in and let you try out their e-fans in your truck to rule out your fans as being the problem!! I would for sure if you lived closer to Oregon, let me know if you wanna drive up my way!! :)

Cmon Texas, can someone help a brotha out on this one!!

---------- Post added at 06:30 AM ---------- Previous post was at 06:26 AM ----------

Also, have you tried to run the fans with the green A/C wire DISCONNECTED to see if the fans work any different? Just an idea!

Also, for comparison reasons for ya, my fans will kick on and off with the A/C off and the selector knob on the defrost and defrost/floor mode and not kick on at all with the vent, vent/floor, and floor mode selected!

[bottomline2000]

Riviera I really appreciate the offer. Its all good. I will find the problem eventually. I don't want to pass a problem on to anyone else lol.

I have tried running the fans without the a/c tap and the same thing happens, fans run on low. The problem has to be in a wire shorting somewhere. Just don't know where and how. I'm going to check my ground wires. I did have my trans replaced last year, but that was before the fans. who knows something may be disconnected.

based on your a/c tap mine works fine. I can do the same and the only way I know mine cycles the same is both fans go to high like yours probably only cycles the one to high, difference is when the compressor turns off my fans cycle to low regardless of engine temp. If they would just turn off I would be good as I'm sure the computer will turn them on at the right temp.

I need to figure out what is causing the computer to ground the relay to activate the fans.

[sparg93]

the Blue42 pin, can someone explain to me how to tap this into the computer? Any photos available? (i've never messed with a computer before)

[sparg93]

anybody?