6.0 L Truck engine fan control pins

[JohnL]

A friend of mine has been working on a 6 L truck engine conversion with an aftermarket harness and a 99 Camaro OS and PCM. The fans don't switch on. A search on the Gen III section here shows the fan pins as 42 on C1 and 33 on C2 for the '99 PCM, but there's not much on where the 6L fans connect. The only diagram I can find says Pin 36 on C1 and it's Dark Green. Can anyone please point me in the right direction?

John

[ChipsByAl]

Your search of C1-42 and C2-33 are the correct terminals for the 99 PCM. The PCM and OS will dictate where the pins are, not the engine it controls.
Al

[JohnL]

...The PCM and OS will dictate where the pins are, not the engine it controls.

Thanks Al, I'm clear on that point, but the reason I related it to the 6L engine is that the engine harness was purchased to be compatible with a new crate truck engine, and I need to know if any of these later OS use different pins to drive the fans, and if so, what they might be.

Thanks,

John

[ChipsByAl]

What year and OS are you looking to use?
AL

[JohnL]

I'm using a '99 Camaro OS. I was looking to see if I needed to change either the OS or the wiring to make them compatible, but I found out that the fans are only wired to pin 33.

The harness is an aftermarket system that looks good, but is a dog's breakfast in terms of fan setup.

I've now got the fans running after working out using the bidirectional mode in EFILive that only the "High speed" mode switched the fans on. I then set up to drive the fans off the Fan 2 setting in the EFILive tuning tool, and immediately blew the single 30 amp fuse that covered both fans! I disconnected one of the fans and it's obvious that the system needs another relay.

This would only work with the "series parallel fans" setting in EFILive, even though the fans only run off pin 33. Using the Auxiliary fans setting with control of the Fan 1 setting in EFILive didn't work.

Thanks for checking it out anyway Al,

John