A/C issues

[Don N.]

The A/C had gone out of my E70, so I had the compressor replaced. Even after replacing the compressor, the car is not blowing cold air. I've had both an independent shop and the dealership look at the car, and they haven't been able to find the exact issue with the car yet.


This is what I had done at the independent shop:
Replace AC compressor
Reset everything - gets signal readings at AC compressor
Freon added to specifications


This is what the dealer told me :
AC compressor is not getting signal (which is opposite of what the independent shop told me)
They wanted to change out the engine harness and redo some of the chassis harness in the rear of the car, because they saw some water corrosion on the wires (wanted $2700 to do this)


I am thinking it may be an obscure/random issue, so I am wondering if anyone on here has any possible ideas that I should consider checking out?

[Thecastle]

When the ac is off, does it blow hot air, not it’s just hot because the car is sitting, but hot like the heat is stuck on?

Also, when the ac is on is the shaft on the compressor turning? If the compressor shaft and clutch are engaging then it’s gettimg all the signal it should need. If not then check the voltages on the wiring to verify signal is being sent.

Two things I’ve seen happen are the condenser and filter dryer get plugged when the compressor shreds itself. Typically anytime an ac compressor dies you’ll want to replace those items. The condenser lines trap metal fragments that can plug it or come loose and kill your new compressor. Which could well have happened here.

Also the heater control valve fails, and the heat can get stuck on. Had this happen on my x5 4.8i, ac worked but you got hot air out of the floor and defrost and coolish air out of the vents.

[Don N.]

The air that blows out is warm, but not hot air like the heater is turned on.

The compressor is not turning when the AC is turned on. Using a diagnostic tool, we saw that there was a signal going to the compressor, but it was not causing anything to happen.

I did notice some metal fragments in the old air compressor when we took it out, so I suppose maybe what you're describing could very well have happened as well.

I had considered just getting a used AC compressor and rolling the dice on going through the whole process of installing another AC compressor, but I just had been hesitant to do that. I'll definitely have to look into replacing the condenser and filter dryer as well. I suppose it'll be obvious if any debris got into the AC compressor if it I took it off and saw any metal pieces in there.

[Poppyboy]

Relay(s)?

[Don N.]

I think the AC on e70s are controlled through the ECU and not a relay now, from what I have researched, otherwise it would be super easy for me to try and jump the relay to get the AC compressor to manually turn on.