1964SS

iTrader: (1)

Ok, from what you've described it sounds like your fan relays are already wired up to the PCM correctly. Fan 1 should go to Pin 42 (green wire) on the blue connector and Fan 2 should go to Pin 33 (blue wire) on the red connector. Don't try and make any sense out of what's on what connector. Both connectors have inputs and outputs on them.

Here is a pinout listing for each connector if you would like information on your computer.

http://lt1swap.com/2001_PCM_CONN_PINOUT.htm

Are the relays completely wired up already? How many wires are conencted to each relay?

Maybe the system was already wired up and working, but had a fail safe switch on the dash as well? Just a guess.

wayne9302

It looks like both relays are wired up, kind of hard to tell because of where they are at but I think there are 4 wires coming out of each. I see red pink and 2 greens on fan 1 and a blue wire replacing the green wire on relay 2.
How do you remove wires or put new wires into the PCM? do you just push them in the slot where the tan plastic is in the slot? what about removing wires once they are in.

Am I correct in assuming that 1 row of the pins on the PCM would be the input and the other the output as shown in my pictures, since both rows have slots numbered the same. What water temperature should should the fan on an LS1 come on and shut off so I can get the right temperature switch.

thanks for your help

ls1nova71

iTrader: (4)

It sounds to me like the fans are wired through the PCM and the switch on the dash was an override so it could be manually turned on. To remove wires from the connectors, you need to unbolt them from the PCM, then take the colored plastic cover off, and pry the little plastic lock tab back and the wire will pull out. Sounds more difficult than it is and once you take one apart it should be pretty obvious how its done. To put wires in, you just push them in from the back side.

There isn't any rhyme or reason to the wires in the connectors, at least to me. Some engineer may know the reasoning, but its not inputs are on one side and outputs are on the other. Look at the LT1swap site, that will tell you exactly what each wire is for.

To test the fans, with the engine off, unbolt the PCM connectors, on the one with the blue plastic covers, find pin 42 and ground it. Just put a small wire in the pin and run it to a good ground, the relay should click and the fan should come on. Try that and get back on here and post your findings.

hookemdevils22

iTrader: (12)

Does the fan come on with the switch? Try it with the key on and key off. If not, flip the switch while grounding blue 42 or red 33, as ls1 mentioned. That will tell you what type of override it is (could be a fan kill for drag racing). The LS1 fan control logic turns off the low fan control when high-speed kicks on. Your relay setup is likely the AAW single fan unit, which uses a secondary relay to control the primary. This is for AC in most applications. In this case, fan low controls primary, while fan high controls the secondary and, in effect, the primary.

For clarification, roughly what gauge are the red, pink, and green and blue wires?

There is another provision for temp sending unit on the head, near cylinder 8.

Adding a wire to the ECU would require you to crimp on the appropriate pins. This is what they look like. They're easy to find on eBay for cheap. It doesn't sound like you need to do this, however.

As for tuning software, HP Tuners or EFI Live are two most popular. I'd personally buy HP Tuners, as it seems to have a slight edge around here. Each are $500.