99-02 e-fan operation with AC on

[tayj6]

This is kind of an old topic, but I've searched a ton and can't find a solution...or even a very recent thread.

Is it possible to have an 99-02 (specifically a 2002) ecm command the low speed fan on when the ac compressor is on? Not using the ac clutch wire.

I have 05+ truck fans installed and wired into a 2002 suburban using an ls1fans harness into pins 42 and 33 in the pcm. What is required to get the fans to come on with the ac when the vehicle is at operating temp? I have had a couple tuners tell me they can do it... But I would like to do it myself.

Thanks for any input!!

[tayj6]

Okay, so I’m adding the 3 wire sensor with harness from bp-automotive. My assumption is that by installing the sensor and wiring it like an 02 Camaro, I should be able to do an 02 Camaro ac segment swap and then have the fans function off of ac pressure like factory. Correct?

[turbo_bu]

If you swap the whole system segment, yes it will work like a Camaro. The problem you could have is if you don't have a variable AC compressor.

[tayj6]

I always see the hptuners guys talking about changing from “analog” to “analog cycling” whenever they are discussing compressor activation. Is that not a setting we have access to in efilive?

[turbo_bu]

Not without a CAX file. The parameter they are talking about is A/C type. I have found it for several OS's, if you wanted to try it.From what I have read, it doesn't always work like you think it should.

[tayj6]

Well, I decided to let bp do it for me for $50...but I’m still real curious exactly what is being changed. They use hptuners which I don’t have so it’s going to be a few days. If it all works like I want it, I’ll still probably try to figure it out on my own as well...just to know.

This may be a newb dumb question, can you just swap the fan segment from a Camaro so the fan control recognizes the pressure sensor for fan control without trying to swap the whole ac segment? I always read about people segment swapping the ac segment from a Camaro but a lot of times they are more concerned about compressor request and activation than fan control.

[Boosted GMC]

The fan settings are under systems. You don't have to do a segment swap. Set G1203 to the type of fans you have, if you want the fans to come on with the ac set G0106 to fan#2 control.

[Jayyk31]

Like.was stated above you need a variable displacement ac compressor to be able to run it correctly with the 3 wire pressure transducer in the f body segment...