Will a truck pcm fun electric fans?
03-26-2010, 07:31 PM
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Will a truck pcm fun electric fans? I am doing research for my swap this summer. I have a LQ4 with computer, I will be modifying a truck harness(from a different truck) Does the truck computer have the ability to run electric fans? I know I will have to add relays, but will the computer tell the relay when to turn on or do I have to use a seperate sensor. If the computer does turn the relay on or off, what pin of what connector? The pin out I have does not show me, but seveal are blank.
03-26-2010, 08:45 PM
#2
Blue connector pin 42 will put out a ground output to run the fans. This is the low speed fan control in the PCM. pin 33 on the red connector would be the high speed, but it does not work on the truck operating system, so you will have to run the fans off of the low speed output only and do a single speed fan setup.
03-26-2010, 10:00 PM
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is that where you wire the fans in siries for one spped and parallel for the other speed? I know I read that the other night, but can not find it now?
03-26-2010, 10:01 PM
#5
electric fans hello millwright1999. from what i hear, the fans can be programmed to turn and off, from the pcm sending a ground signal to the relays. the vendor i used said they programmed my pcm for that operation, but it didnt work. so i ran the fans off the ignition. i like it better 'cause i know when the ignition is on, the fans r on. miami fl, heat is a killer. im running a setup of a 5.3/4l60e swapped in a chevy c10
03-28-2010, 10:30 PM
#8
Seems to work for some people but not others. The high speed fan control on most of the trucks was used from the factory for something A/C related (air recirculation door IIRC?) and I have read that for more than a couple people it would not control the fans, that it only put out a pulsed ground. But I never tried mine, I have the fans set up as a single speed.
