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View Full Version : Air Conditioning not working, need help.



Mr Paul
04-19-2015, 10:18 AM
A few weeks ago my ac quit working, I normally do all of my own maintenance, but I've never done AC work before so I took it in to a shop. They called back and said my auxiliary fan was dead. I told them I'd pick up the car and replace the fan myself, it's certainly easy enough to do. I replaced the fan and guess what, the AC still doesn't work. So now I've decided to get well versed in AC repair and diagnose and fix this myself.

Here are my symptoms. When I turn the AC on the compressor kicks on. I also hear a hissing sound coming through the vents, it is much louder than the sound of the blower motor and only comes on when the compressor is running. The auxiliary fan does NOT come on when the compressor comes on. But the fan does work when the car starts to get warm, so I know the fan works. Since the aux fan doesn't come on with the compressor there is a signal that is not making it to the fan itself.

What conditions dictate that the fan comes on when the AC is engaged? Is it a pressure switch, something from the DME, or something else entirely? Thanks for the help.

feytr
04-25-2015, 08:52 AM
A/C Pump ?

Oli77
04-25-2015, 10:37 AM
Google the old FSR, final stage resistor. Think that guy has control power over blower motor.

WOLFN8TR
04-25-2015, 10:39 AM
Google the old FSR, final stage resistor. Think that guy has control power over blower motor.

I was thinking the same thing. Usually what goes out.

Mr Paul
04-26-2015, 05:25 AM
Google the old FSR, final stage resistor. Think that guy has control power over blower motor.

I don't think it is the FSR, as my blower motor is working fine. It is the fan mounted on the radiator that is not coming on.

Also, yesterday I hooked AC gauges to the high and low side ports of the system. The low side read 30 psi, which is about right and the high side read 75 psi, which is about 50 psi too low. I'm not sure what to think about that though. Refrigerant low?

kakashi169
04-26-2015, 01:22 PM
Can it be the condenser? My A/C is not working as well and last time I checked, my shop told me that it was the condenser.