help is needed. cooling fan issue.
 

I have an 02 Silverado that I did the electric cooling fan mod. Got the harness kit(can't remember who's it is). It's run by the computer. Fan motors are good. What's going is when the ac clutch is engaged the fans turn off. Soon as the clutch disengages the fans kick back on. It's got me a little baffled. Any help will be appreciated.

Who wants to defend the 1 wire fan harness this time?

Figured out is the Nelson harness.

What are you talking about when you say one wire harness?

Great. Nelson was the one defending his 1 wire harness the last time it came up. Only 1 wire going to the pcm instead of 2 for fan control.

OK. So. Back to the original question. What would cause the problem I'm having?

Check Relays

I will; still nothing wrong with running it.

His issue isn't the design of the harness, he's having an issue that isn't normal and needs help.

Try this:
Be sure you're tapped into the correct ac wire.

Touch the blue wire to ground, both fans should turn on LOW speed.
Touch green ac harness wire to 12volts, one fan should turn on HIGH speed.
This will verify the harness is working correctly.

send a pm if you need further assistance,
thanks,

Fans are operating correctly as far as high and low speeds at the temps they're set to come on. As the ac clutch cycles. The fans are off as the clutch is powered. Fans come on when the ac clutch power is turned off. I ran the temp up to 210 with the ac on. Turned the ac off and the fans kicked on high till it came to the off temp. If the fans are running andi kick the ac on....the fans shut off.

Nelson performance..... I'll try your suggestion tomorrow for the harness check.

Your fans will not operate on high speed with temps with a 1 wire harness.