I had eliminated all the other common causes and so I was left with the AC amplifier/ HVAC control module vs the speed sensor and the evaporator core. The HVAC control module was the easiest and cheapest next step so I went with that
- a few months ago, the AC light started blinking and system wouldnt come on. I identified a bad mag clutch and had the compressor replaced by an auto shop earlier this week. They said they charged it up, but couldnt get power to it.
- I took it home, figuring, Id try to handle it if it was something easy (like the relay)
- A new mag clutch relay didnt help and using the fog light relay doesnt work
- The low pressure refrigerant reading is 40 PSI
- The system works if I bypass the relay in the fuse box with a paperclip (clutch engages and blows cold air).
If I disconnect the pressure switch, the AC light stays on, but blows warm air. If i reconnect, it blinks and nothing
- So I have a new compressor (denso OEM part), the refrigerant is filled to adequate pressure, and I can get power if i jump the relay. This seem be the major components
- I checked all the electrical connections to the compressor and the pressure switch and all seem fine.
I thought I was left with the thermister (AC evaporator temperature sensor) or the coupler that ties the compressor to the engine RPMs
Heres another thread
AC light flashing, relay is good