dsrour

Has anyone run aftermaret a/c through the E38 pcm?
Looking at the C6 ls7 a/c schematics the A/C request comes to the pcm from the a/c module then bcm via serial data.
So I was wondering if its possible without the bcm or could you use a bcm as well.
The earlier pcms allowed for manual operation of ac.
any thoughts appreciated

ls1nova71

iTrader: (4)

You would have to also use the A/C module, because to the best of my knowledge there's no way to reproduce the signal that it sends to the PCM via the serial data line. I've been fighting the same problem on my 6.0 conversion. If you could mount that module/switch, and the pressure sensors, it should work.

dsrour

thanks. looking at schematic looks like ac module goes to bcm then serial data to PCM. I wonder if you could use these modules just for AC. I guess the alternative would be use an ls1 PCM
w 58to 24 convertor

rsz288

Much simpler to use an LS1 PCM. Which would give you cruise too! The BCM needs the right ignition switch and key just to wake up, let alone do anything. It also validates with the instrument panel and ECM. So if you have a complete take out setup and if you have a buddy who is a GM tech and good with a tech II, that would be a benefit.

dsrour

Maybe I'll look at using the LS1 pcm. Easier tuning too w/ ve tables.
Which LS1 is considered best these days?
What TB would you use? and DBW pedal?
Dang just finished my E38 harness too!
thanks for the advice
dave

Jones'n

Why not just wire the A/C in and bypass the computer?

dsrour

That would be way too easy. Actually taking advantage of the PCM AC controls makes for a smoother operating system. The PCM does things like bump up the idle before clutch is engaged.
I have it wired this way now with the LS1 and was hoping to do it with the LS7 and E38 PCM as well. The increasing sophistication of the systems with climate control, zoning etc, makes it much more challenging.