What's everyone doing for the pressure switch with an LS1 and keeping AC? The third-gen one is a simple two wire contact closure switch. The LS1 uses a 5v reference 3 wire sensor with a return.

It looks like the PCM really would like to see the pressure change, so I think I will have to go with the LS1 style. I don't have one in front of me, does anyone know if it will thread into the 3rd gen line where the old one goes?

Thanks,

Kevin D.

 

I am not 100% sure, but the obdII LT1 used a hi pressure, low pressure, and a temp sensor for the ac system. The temp sensor is the three wire switch with the 5V referrence (grey wire). I am pretty sure the computer doesn't need this and won't throw a code.

 

I've got the service manuals. Aside from blower motor control, there are six wires for AC and they all go to the PCM.

Clutch relay
Clutch status
AC request
AC pressure switch ground
AC pressure switch 5v ref
AC pressure switch v input.

Looks like the LS1 did away with a temp sensor and went to a single pressure sensor. Pretty sure the AC will not turn on without it.

If I can't find one at the parts store I'll snag one off the 99 TA parts car I'm getting next weekend. Hopefully it's the same threads or easily adaptable.

Kevin D.

 

from everything I have seen, the computer receives the ac status so it can idle the engine accordingly. Of course, this is for the later LT1 though.