AC Compressor Won't Turn On After Replacement

Hi guys.

2008 2.7l - my AC died the other day with loud SCREEEEEECH! And the AC button started blinking.

I went ahead and replaced the compressor. After drawing a vacuum, I tried to charge the system but the compressor is not being commanded on.

I verified that the pressure switch is closed (zero ohms) and I have about 70 pounds from the R134a on the low side. The AC fuse is not blown. The AC button no longer is flashing g.

If I jumper 12v directly to the compressor it starts and runs fine.

Something is preventing the compressor from being commanded on, but I don’t know what - and I don't have a wiring diagram.

What am I missing here? Any ideas?

 

Watching

 

How did you jumper 12V to compressor? Have you check the AC MAG relay?

 

Sounds like the relay

 

Did you by chance flush the system? When the compressor goes like that, bad things end up in the lines. If you don't flush them out, the new compressor will clutch its chest pretty quickly.

 

Hi guys,

Thank you for the suggestions.

I unplugged the high-side pressure switch and jumpered the pins together. The system then turned on normally and all is well - even after plugging the switch back in. The compressor runs very quietly and the system is cooling nicely.