PWM cooling fan(s) control using ECM

[parsonsj]

Originally Posted by Vince

Yes, there should be an AC input wire right? Let me see if I can find the pin #

On the E67, the A/C request signal is via CAN request from the BCM, not a signal wire.

[Vince@Meanstreets]

Originally Posted by parsonsj

On the E67, the A/C request signal is via CAN request from the BCM, not a signal wire.

ECM fan request pins are a grounding circuit right?

[samckitt]

Originally Posted by parsonsj

On the E67, the A/C request signal is via CAN request from the BCM, not a signal wire.

So with the GMPP controller (I believe it is an E67), there is no point adding the AC pressure sensor/switch? Unless the BCM is added?

[parsonsj]

Originally Posted by Scot

So with the GMPP controller (I believe it is an E67), there is no point adding the AC pressure sensor/switch? Unless the BCM is added?

It would be better if the A/C request went through the ECM so we could have compressor protection features (like RPM limit, WOT cutoff, overheating protection, etc.). But we don't, so all we get are fan control features via the A/C pressure sensor. Is it worth doing? I think so, but it isn't ideal, and the system needs a binary switch to protect the compressor since the ECM doesn't/can't.

If only Vintage Air or InfinityBox (nee ISIS) had support for GM's A/C CAN-bus request...

[samckitt]

Fits like it was made to go there. LOL

[samckitt]

Anyone else looking for one of these connector bodies for the PWM fan module? If so I will order a few more.

[cjfirstgen]

So what options does one have for integrating with an aftermarket ECM like in my case a FAST XFI? The FAST XFI ECM only has a negative relay control for fan on/off. I was reading about the Derale PWM controller but not a fan of the push in probe. Other options for a stand alone PWM?

http://derale.com/products/electric-...n-probe-detail

[65C6Corvette]

Originally Posted by samckitt

Anyone else looking for one of these connector bodies for the PWM fan module? If so I will order a few more.

Sam,

Get me two… Thanks, Dirk

[Old66Tiger]

Good thread. I have a few questions...

I am running an E38 ECU and currently have it set up in discrete mode with a pair of spal fans. I understand that programming is required to switch to PWM mode. I also understand that a binary or trinary switch is required to control the vintage air compressor for over or under pressure conditions. My question surrounds the need for a high pressure signal from the a.c. system to kick the fans into high speed. Is it possible to let the trinary switch send a ground signal to the ECU to send the fans to high speed when the a.c. system requires it? I have an a.c. input from the speartech harness for an a.c. input. Otherwise I will need to wire in a second switch into the #6 line between the condenser and the evap.

[samckitt]

Originally Posted by 65C6Corvette

Sam,

Get me two… Thanks, Dirk

Dirk, Not 100% if/when I will order them. If there is enough interest, i will, & I will let you know.
Thanks