Strange A/C problem
 

Hi, strange problem... I have a 2004 Pacifica. The temperature control unit went bad (display off, fixed, cannot change settings), so I bought a new one. When I install the new one, everything works fine EXCEPT the A/C turns on, and after a few seconds, turns off... after a while it happens again, but it never stays on.

So, I reinstalled the old BAD temperature control unit, and, even though I can;t change it, the A/C works fine!!!!!!.

SO I returned the new unit, replaced with another one, and it is the same... with a working unit, the A/C turns off, but with the bad one, the A/C works perfectly (but of course, I cannot change the settings...) Any ideas???

Same thing!
 

Hi,
I have a 2004 Pacifica. I ALSO had the a/c control panel go completely black, then when I replaced it, my A/C cycles and doesn't stay on. Really, really sucked in the summer in Sacramento.

Replaced the A/C pressure sensor, checked pressure on high and low ports (fine), replaced blower motor resistor, checked about everything I can think of. If I jumper across pins 20 and 87 in the relay, the A/C compressor stays on. I grounded pin 11 from the PCM and it clicks on the compressor. Everything checks out and I am at a loss.

My last resort is replacing the PCM, but would love to know if you figured this out!