2000 Silverado E-Fan Question...

[Mr. P.]

The trigger (ground) wire goes to Pin 42. On your PCM, Pin 33 is internally wired for another purpose; on the trucks, the PCM does not support 2-speed efan operation until 2003 and the redesign of the AC climate control circuit.

Mr. P.

[GAMEOVER]

The trigger (ground) wire goes to Pin 42. On your PCM, Pin 33 is internally wired for another purpose; on the trucks, the PCM does not support 2-speed efan operation until 2003 and the redesign of the AC climate control circuit.

Mr. P.

OK, but what would be causing the fan to stay on, on start-up? Maybe the PCM is bad? Maybe the 1999-2000 OS don't support e-fan operation!
Every 01-02 0411 PCM that I've used for transplants has always worked...Man I hope I don't have to change the OS or PCM...

[Mr. P.]

OK, but what would be causing the fan to stay on, on start-up? Maybe the PCM is bad? Maybe the 1999-2000 OS don't support e-fan operation!
Every 01-02 0411 PCM that I've used for transplants has always worked...Man I hope I don't have to change the OS or PCM...

Pin 33 in your PCM is used to control the recirculating door (climate control); when Delphi made that PCM that pin is grounded all the time. We have run into the same issue 3 times now installing efans into pre-2002 trucks, I resorted to a custom relay box with the high trigger wire plugged into pin 42 and the low trigger wire activatedby the AC compressor.

If your AC system has the simple AC high-side safety switch then your PCM will only support one fan circuit; if you have the later (2003+) high-side pressure sensor then your PCM will have both the internal circuit and OS support for dual-speed efans.

Mr. P.

[gmh308]

Is your A/C all gassed up to pressure?

[GAMEOVER]

Yes, AC is gassed up... I've tried different pressure settings and fan is still on....

[GAMEOVER]

Pin 33 in your PCM is used to control the recirculating door (climate control); when Delphi made that PCM that pin is grounded all the time. We have run into the same issue 3 times now installing efans into pre-2002 trucks, I resorted to a custom relay box with the high trigger wire plugged into pin 42 and the low trigger wire activatedby the AC compressor.

If your AC system has the simple AC high-side safety switch then your PCM will only support one fan circuit; if you have the later (2003+) high-side pressure sensor then your PCM will have both the internal circuit and OS support for dual-speed efans.

Mr. P.

Mr. P.
I am using PIN#42, I'm not using pin#33
That makes me believe that pin#42 is grounded all the time too....What else would it be?

[67SS509]

When using that OS select the "Auxillary Fan" instead of "Series Parallel Fans" and it will work fine. Just ignore fan settings for fan #2.

[GAMEOVER]

I already tried that, no luck though....

[67SS509]

I already tried that, no luck though....

Missed that in your posts. Don't have access to my laptop right now but I have done that year model. It was pin 42 and I used Aux Fan setting but can't say which OS right now. The OS can make a difference.

I suggest taking a digital volt meter from 12v to pin 42 and see if indeed the PCM is turning the fan on.

[GAMEOVER]

Missed that in your posts. Don't have access to my laptop right now but I have done that year model. It was pin 42 and I used Aux Fan setting but can't say which OS right now. The OS can make a difference.

I suggest taking a digital volt meter from 12v to pin 42 and see if indeed the PCM is turning the fan on.

Yeah, that's what I'm starting to think, OS must make a difference...