I have both fans to 1 relay. Not worried about high and low speeds. When I ground my relay the fans come on like they should. Seems as the computer is not putting out the ground output needed to turn on the relay? Could I have the wrong wire? I am using pin/wire 33 from the red connector that I got from this diagram: http://www.lt1swap.com/2001_PCM_CONN_PINOUT.htm

my motor was from a 99 camaro could it be different? I am also getting coded p480 and 481 fan 1 and fan 2 circuits. Any one help me out.

 

Pin 33 on the red connector is the high speed fan circuit. Generally if you were only using one fan you would hook to pin 42 on the blue connector which is the low speed fan. What temp is the PCM set to turn the fan on at? Is it reaching that temp?

 

Check out this diagram, maybe itll help you.

If you look at the diagram you see that the pcm actually GROUNDS the circuit to complete it, make sure you follow that type of wiring.

Also, like G-body (listen to him, he's a genius on here) said, use blue 42 instead, and maybe find out and tune the start / stop temps.

 

This is a very important question. The factory fan settings are a lot hotter than you (at least I) would think it would be. Without an editing program or possibly a handheld programmer you aren't going to be able to read and tell what the setting is. You also can't read real time what the computer thinks the temp actually is. This is huge from a troubleshooting angle.

In HPT Pro (because that's what I have) I can read and adjust the fans on / off times for both "low" and "high" speed. I can also force them to come on at any time with their scanner for testing or set a timer for hot conditions to run the fan with the key off if certain criteria are met.

If you're going to do more than one conversion or are simply curious about how your car works, buying a laptop based tune / scan program is some of the best money you can spend.

 

I will try hooking it up to the low speed to see what happens.

 

Using the low speed fan wire worked. Thanks