efan problem

[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 .

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 ([email protected]).

 

[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?