Automotive Air Conditioning Information Forum (Archives)

jamesawooten on Mon May 27, 2013 8:59 AM

Year: 1995
Make: Geo
Model: Prizm
Engine Size: 1800
Refrigerant Type: r134a
Ambient Temp: 70
Pressure Low: 45
Pressure High: 180
Country of Origin: United States

Our 95 Geo Prizm LSI has some issues with the A/C that I'm stumped on.

So far:
1 - A/C light NOT on when depressed.
2 - Pressures look good and getting 47 degree air out on a 75 degree day after removing a/c relay and jumping 12v to compressor.
3 - low pressure switch is good, pulled combo switch on low side and verified operation by shorting low pressure switch LR and YB wires.
4 - fuses are good.

Where to next folks? Looks to me as if either the A/C amplifier is bad or it's receiving an input from somewhere that's telling it to shut down.

mk378 on Mon May 27, 2013 10:14 AM

Without having looked at a schematic of that particular car I can offer these general suggestions:

Wiggle the fan switch and see if A/C ever kicks in. The fan switch probably has a separate circuit to enable A/C, it would be closed circuit in all positions except off.

If it has an A/C amplifier, remove the amplifier unit from the car, open it up and resolder all the connections on the circuit board. Put back together and try again.

The bulb in the button could be burnt out. Generally A/C amplifiers will make the light blink if trouble is detected.

jamesawooten on Wed May 29, 2013 7:56 AM

Here is the schematic for the 1995 Geo Prism (also the Toyota Corolla)

The fan switch doesn't seem to have any effect - tried a bunch of back and forth and wiggling as well.

The a/c light is good - it flashes briefly as the ignition switch is turned on.



Edited: Wed May 29, 2013 at 8:06 AM by jamesawooten

mk378 on Wed May 29, 2013 5:01 PM

Your picture does not load.