New switch is in and system recharged. Was unable to obtain a 210 psi on the high side to determine if the new switch signals the fans to “high”. Apparently that part number serves three switches, and the first one I ordered albeit identical in all regards, would not accept the electrical connector ...

John for the win. There was a Schrader valve under the switch. I discharged and left about 10 psi in the system. Removed the switch and low and behold there is a Schrader valve hissing at me. I took pick pics of the switch to get part a part number. There was an O-ring on the Schrader body which was...

Red line is pointing to a mating surface. Yellow line is pointing to the boss which the switch mounts. The blue is pointing to the base / female fitting of the switch. The switch was sending a high pressure signal (verified with scan tool) which was commanding both fans to max in every “key on” situ...

Pic. Had to resize

I took a pic, but is too large to upload here. I’m struggling to find a part number for that switch, so I was going to remove, inspect and or take to the parts house in hand to compare to the replacement, As mentioned I got 4-5 turns on it before it began leaking, which is ample to have a leak. It a...

Ok. Went to pull the high side fan pressure switch. Unscrewed it about 4 turns and it started hissing. Waited a moment and it started hissing heavier and would not stop, so screwed it back down. Sealed up.

Is there a Schrader valve under there? The mounting flange doesn’t look very deep.

Yes. I watched that blend door actuator (both of them) for 10-12 cycles with no anomaly. Then it went from hot to cold and stopped about 3/8” shy of full cold. Then that was its range for several cycles before returning to normal. I was going to ask if there was a valve under that press switch. Than...

Just posting a follow up for posterity. Had a cooling fan issue (fans on high all the time) and the scanner live data showed a AC PRESSURE - HIGH. (Key in, engine off, AC not run). After several days of having the fuse for the fans pulled I took the car to a mechanic with a GM TECH2 scanner. Put the...

It was a “Dry Cold” up north at least!

Yes! We moved to AZ from the upper Midwest and the heat has uncovered some previously acceptable tired components.

The clutch cycling at 2500 RPM has me wondering if my charge is low. Or is it just doing it’s thing? Hard to hear or feel it from the cab so it may have always done so.