I recently installed electric fans on my truck and wired them to my pcm but they turn on as soon as i start the truck and im not sure why they are. I'm hoping someone could take a look at my tune and see if they can find whats causing it? i have a feeling it could be in the ac settings of the fan control because i don't have any ac hooked up. thank you.
Can you command them on and off with VCM controls?
Also how did you wire them, High Low speed like F body or just 2 fans?
Just so you no you have your off temps set at 284 degrees. They will never get to that temp to turn off fans.
Last edited by gagliano7; 06-21-2013 at 05:42 PM.
they are wired for a two speed fan and yes i can command them through the vcm contorls.
Your fans are set to turn on when the PCM sees 175 degrees. According to the settings, your fans will turn off when the PCM sees 284 degrees. WAY too high. 2 questions...
1. What temp thermostat are you running?
2. How is your relay wired? If its a GM PCM, your wire should goto GROUND on the relay.
1997 Black Curse SEi, 4th Engine, 2nd trans.
2000 Chevrolet Blazer LT 4.3L
2002 Chevrolet S-10 LS 5.7L
the relays are wired one side of the coil to ignition power and the other to the pcm. Iam running the stock thermostat i believe 186 but im going to be putting in a 160. I know its pretty much useless to have my fans turn on before my thermostat opens i was just experimenting.
I meant was, when powering the relay, it takes 12v + and -. Did you connect the - or + side to the PCM?
1997 Black Curse SEi, 4th Engine, 2nd trans.
2000 Chevrolet Blazer LT 4.3L
2002 Chevrolet S-10 LS 5.7L
pcm to the negative side the pcm. the pcm pulls the line low to activate the fans
Not to hijack, but I was thinking of doing this to my truck 00 Silverado 5.3. How did/do you determine where to add the control wires? I've compared harness wiring diagrams between the truck and an 02 f-body and I see the low speed pin on the fbody is listed as not used on the truck, but high speed is used for HVAC rec door on truck. I'm probably just an idiot, but I'd like to know how it could work.
02 35thSS,A4>M6, 3.73 gear, PRC stg 2.5 5.3L heads,TS torquer v2 cam 232/234 .595/.598 112LSA,CAI,36lb injectors, shorty headers, gutted cats, racetronix pump w/ hotwire, HP Tuners,NGK WB through EGR, Bunch of UMI and Spohn susp. parts. All work done by me, and tuned with the help of some great people on this forum!
Reply With Quote