Originally Posted by
CaptArt
UPDATE: Finally figured out how to extract the alternator and after a few bruises on my arms I have installed the new one and a new serpentine belt (I figured as long as I had it off it made sense to put a new one on). Car starts and runs fine; however, now I have no air conditioning! It appears the clutch is not engaging, fuse is fine, switch works (you can hear the relays click) but nothing but warm air. Before assuming it is the compressor, is there anything else I can check to see why its not engaging?
Thanks for all the support, as a very senior mechanic I can handle all kinds of engine issues but these electronics frustrate the daylights out of me. I think its time to trade back for a pre-1970's vehicle that I am more comfortable working on.
1) I remember, once a LONG time ago, around 2010, this happened after someone changed the idler pulley and belt.
The guy managed to route the belt such that the A/C compressor was running BACKWARDS. (I can't remember if it was a Crossfire or some other car... may have been something I read on Ford Ranger Forums.)
2) What "relays" are you hearing click? There is no relay that activates the A/C clutch, the clutch is activated via a large pass transistor on the main Climate Control Module board. The only "click" you might hear is the clutch's electromagnetic actuator or the servos in the throttle body. If you hear a click on pressing the A/C button, I think your clutch is engaging.
3) The Climate Control Module will not engage the A/C clutch if:
There are certain cooling system errors/alarms seen by the ECU, it tells the Climate Module to not engage the clutch.
The pressure sensor reports too high or too low pressure in the refrigerant system (you damaged a line and let the gas out, or you knocked the connector off the sensor, I have no clue how you'd do that just changing the alternator).
Other issues I don't know about.
Just know that the system, like all systems in modern cars, is tied to other systems and is under supervisory control of the ECU.