E fan issue

[livingez_123]

I put the OEM fans on my 01 Denali. I used the OEM harness. The ac control works perfect, but I cant get the low speed fans to turn on. I have 2 custom tunes and neither one works. The harness has been tested both on the truck and on the bench, and all works fine. I tested the pin at the ECM and can trigger the low speed fan like it should. I replaced the ECM pin just in case, but that didn't work either. I have gone through the wiring from ECM to the relays. I checked the lead from pin #42 with a test light, and it won't trigger at any temp. I'm out of ideas.
The tunes are coming from the guys at Diablo.
Any thoughts?

 

[YukonXL04]

Are you sure the truck is getting up to temperature to signal the fans to come on?

 

[livingez_123]

Are you sure the truck is getting up to temperature to signal the fans to come on?

Most definitely, I had my tuner plugged in, and I sat in the driveway and watched the temp go up. I finally kicked the ac fan on when it hit 240°, and it sure cooled down fast. So I think it's getting up to temp. Driving around the temp never went higher than 198°

 

[Rivieraracing]

Just got your message, can you post up the wiring diagram that you have for the '03-'06's, I'd like to take a look at it!

 

[JennaBear]

I believe the problem is that you have an 01. Need to change OS.

 

[livingez_123]

I believe the problem is that you have an 01. Need to change OS.

Explain please Jenna.

All of the people I have talked too say it's just a programing change. LS1 Fans, Nelson say the same thing, it should work with the fans turned on in the programing.

 

[livingez_123]

Just got your message, can you post up the wiring diagram that you have for the '03-'06's, I'd like to take a look at it!

Here you go.

Other than the AC being changed to a 12v trigger, it's should work.

 

[Time2Kill]

*EDIT*

Nevermind, just realized it was a Diablo tune.

 

[Rivieraracing]

Here you go.

Other than the AC being changed to a 12v trigger, it's should work.

Got your email and printed it out to look at it tonight and show some of my electrical smarter coworkers!

 

[livingez_123]

I think it just might be the ECM/PCM. There is nothing else it can be.