Help with 05" E-Fans and harness into a 00"

[lowpost99]

I have been researching my e-fan upgrade, but I'm falling short of wiring my relays. Ok, first I'm not using any PCM programming or plan to nor do I want to over cool the engine with both of these fans so keep me honest if I'm repeating flawed information here. I got dual OEM fans and the complete harness from an 05" and I read that a thermo switch (temp) and the ac compressor grounds can be used to run the driver's side on high(temp) and both on low(AC on) using the three OEM relays at the end of the harness. I've also read that I need two 5 pin relays and the same triggers a thermo switch and the +green wire from the AC compressor. Bottom line is I have a wiring diagram that I don't fully understand, and I need a little help getting either of these options wired up at the relay side. Here's what I think I need for either option.

OPTION 1 OEM relays 1) where do run my thermo switch wire to? 2) where do I run the wire splice from the AC compressor to? and which wire is it? I read some where that the 05' trucks use ground vs the + green wire, so that would not be the target wire to splice correct? The relay power and ground are straightforward enough to put on posts, but I don't understand what is considered to be the relay output wire . This is mostly taken from this post https://www.tahoeyukonforum.com/threads/e-fan-help-needed.81341/

OPTION 2 is wiring up according to Chris's 02' how to, but I'm at a loss as to how to wire up the 5 pin relays with power, the 2 fans, and the input from the temp switch, and the + wire from the AC compressor.

I'd love some sketch help from anyone that's done either one and has the fan cycling on/off (temp) and both on low for (AC), but not over cooling the engine. Thanks up front, I've got the clutch fan off and the new fans mounted and all my parts for the temp trigger and the AC wires ready to go!

 

[Scottydoggs]

if you do it via the pcm tuning they can set the fan temp lower. but to be real here, making it run a lot colder is not good, few degrees is one thing.

your engine was made to run at 210 for a reason, where it runs its best and gets the best mpg too. you are not dealing with a 60's or 70's engine. you force it to run colder and the pcm will know it and set codes for low temp.

 

[Chris2144]

I started a new job haven't been on in afew days sorry about that. So for your temp switch when you run it back to the relay it is going to be controlling the ground of the relay to turn it on. If you are using a two pin then you and run it + but the one like I posted uses ground as it opens continuity to the body of the switch. For the ac just run from the green ac + wire down by the compressor that will get you running and cooling. From there we just need to figure out how to get low speed for the ac using the OEM relay set.

 

[Chris2144]

Oh and don't worry about over cooling. Your thermostat will close to keep the engine temp where it needs to be however in this heat I doubt it will ever have to

 

[lowpost99]

I went with option one, and I used the oem wiring harness. I need confirmation that there should be a ground wire pigtailed in to the black fan wire. I may have cut it off when removing the harness from the donor truck. I'm using a 5 pin relay 86 - ac wire 87 and 86 are ground and 30 is the line to the blue wires in the oem relay. This is supposed to change the - ac signal to +, and the thermoswitch is run to ground and to the green wire in the oem relay. The red power cable is run to a post at the fuse box. The problem is that when I reconnect the negative cable back to the battery, the fans come on without the car running or in the ACC on position. Any ideas why this is happening?