I have a bit of a "chicken or the egg" scenario going on with my wife's 07 V6.

BACKGROUND

Sunday:
We were driving together when the A/C stopped blowing cold consistently.
A/C would alternate between hot and cold air.
Engine would occasionally shutter while idling.

Monday:
Wife drove it to work.
A/C still alternating between hot and cold.
Engine would occasionally shutter while idling.

Tuesday:
I drove it to work.
A/C was cold and no engine shutter.
(It magically fixed itself... right? )

Wednesday:
She drives it again. No problem OTW to work, but OTW home...
Temperature gauge creeps up while idling; returns to normal while moving.
A/C just blowing hot.

I pop the hood to confirm that the engine cooling fan isn't coming on at all.
I also noticed the A/C clutch comes on but doesn't stay engaged.

I've checked the relays (24, 25, 28). All good.
I plan on checking the other fuses associated with the fan/ac/pcm and the fan resistor when I get home.


QUESTIONS

1. Which is more likely to be the culprit? The A/C Compressor or the Engine Cooling Fan.

2. Was the cooling fan steadily failing the whole time, and just gave up the ghost yesterday?

3. Is the A/C clutch not staying engaged to prevent the compressor from overheating via the PCM?

4. Would a short in the A/C compressor mess with the PCM causing the engine cooling fan to not engage?

 

A new engine cooling fan and a few fuses later... all is well.
Wife's ride is back on the road.