From me. I have more coming. Should be here in a week or so.

After a considerable amount of debugging, testing components, and general frustration and angst... I called GM Powertrain today.

Here's why: my system doesn't work. I can get discrete fans to work, no problem. But not a PWM fan. I've tested all the components individually and together. I built test harnesses and even sent my fan controllers off to be individually tested by a small company in Wisconsin.

All work fine.

Today, I got the GMPP help number and talked with tech support. They tell me that the fan PWM circuit is disabled in the GMPP crate motor ECMs in an effort to simplify tech support and reduce warranty claims.

So: you guys with GMPP crate motor E67s... how did you get your PWM fans to work?

Related: I called back and asked about AC pressure input support, along with reverse lockout.

The tech claimed there was no AC pressure support, and wasn't sure about reverse lockout. I managed to get him to take the action to ask Engineering, and I'm to get an email response.

So, here's what I've learned last night/today. My E67 (GM PN 12636660) started life intended for 07-08 Hummers. I think it's true that 07-08 E67s are incompatible with OS's written for 09+ E67s.

Given that, it seems I'm stuck. Getting a later E67 and a newer OS (like from a ZR1) is beyond my current abilities, I think.

I have read that HPTuners has an OS patch to support PWM fans, but I can't seem to find any such animal.

Anyway, that's the situation as I see it. Am I wrong? Would it be doable to get GM's ZR1 tune working with my crate motor LS9 if I got a newer E67?

Paging Dave Mikels, paging Dave Mikels. Dave Mikels to the E67-challenged section, please!

thanks!

The GM tech was right. The ECU isn't reading the A/C pressure.

And, so, continuing on with this thread where I'm talking to myself, I've picked up a salvage yard E67 (from a 2011 Malibu) and it's on its way to Austin where I'm having a 2011 ZR1 OS loaded on it.

From there, I'll move my GMPP LS9 tune to the ZR1 tune. I'm hopeful that this new setup will read A/C pressure and support PWM output.

Thanks for posting john.

I'm curious who you are sending it to here in Austin? Assuming you meant the city and not a person? :headscratch:

Dave Steck at Finspeed said he can fix this for me.

Another (related) question: does anybody have a line on the voltage vs pressure map of the GM AC refrigerant sensor (AC Delco pn 15-51258)? I've been in contact with a vendor about a standalone fan controller for AC and engine coolant temp.

I've done some googling without much luck, though why I would expect anything other than bad luck is a good question. :bang:

I think the sensor map would be resistance in ohms versus pressure. I am guessing this is something you could measure with a little ingenuity, a tank of MIG gas, a regulator and an ohmmeter. :thumbsup:

Don