Intermittent AC compressor
08-09-2018, 12:32 PM
#1
Three Wheelin'
Thread Starter
Intermittent AC compressor
not a common occurrence, and may happen a few times in a week or not at all.???
AC will be blowing cold and properly, and then, I believe, the compressor will cut off. AC button light is still on and
no fuses blow, but no more cold air. does not blow hot or even warm. just feels like normal vent air.
to remedy, I push the AC button off, wait for a minute, or less, push the button again, and the air will be working fine.
only once did I have to do this reset twice, on the same drive. it works fine thereafter. this solution has yet to let me down;
the AC always comes back and blows cold. could be a relay sticking?
recently drove on a few hour trip in each direction, with no issue.
AC will be blowing cold and properly, and then, I believe, the compressor will cut off. AC button light is still on and
no fuses blow, but no more cold air. does not blow hot or even warm. just feels like normal vent air.
to remedy, I push the AC button off, wait for a minute, or less, push the button again, and the air will be working fine.
only once did I have to do this reset twice, on the same drive. it works fine thereafter. this solution has yet to let me down;
the AC always comes back and blows cold. could be a relay sticking?
recently drove on a few hour trip in each direction, with no issue.
08-09-2018, 08:55 PM
#3
Rennlist Member
Yesterday I bypassed my freeze switch with a 5 amp fuse on the ‘93 GTS as an experiment. Compressor running all day now. I had the exact symptoms. I have a trip this weekend to see if this fixes the problem. I will watch out for freezing evaporator and shut it off if I have to. My ‘90 GT coincidentally has the same problem. Will report back.
08-11-2018, 12:04 AM
#5
Chronic Tool Dropper
Lifetime Rennlist
Member
Lifetime Rennlist
Member
It’s possibl that a failing relay would offer the same symptoms. The testing is closely related. Two light bulbs with jumper wires connected. One connects to a connection on the freeze switch and ground. The other attaches to the other side of the freeze switch and ground. Bring the bulbs up onto the cowl, secure with gaffers tape so you can see them as you drive. Then drive with the AC running. Both lights come on. When the compressor drops out, look at the light bulbs. If one is still lit, the freeze switch is open. If both are out, the problem is likely the relay. If both are still lit, there’s a problem in the circuit between the freeze switch and the clutch. Candidates include low refrigerant pressure, dirty 14-pin connection, poor connection front harness to clutch, or the clutch itself. The pair of bulbs gets two of the three most likely. To test the third, make some connectors to get the bulbs connected to the wires at the low pressure safety switch. One bulb out says you are low on refrigerant. Two out say relay. Both still lit points to 14-pin and clutch, wiring, connectors.
08-11-2018, 07:46 AM
#6
Three Wheelin'
Thread Starter
It’s possibl that a failing relay would offer the same symptoms. The testing is closely related. Two light bulbs with jumper wires connected. One connects to a connection on the freeze switch and ground. The other attaches to the other side of the freeze switch and ground. Bring the bulbs up onto the cowl, secure with gaffers tape so you can see them as you drive. Then drive with the AC running. Both lights come on. When the compressor drops out, look at the light bulbs. If one is still lit, the freeze switch is open. If both are out, the problem is likely the relay. If both are still lit, there’s a problem in the circuit between the freeze switch and the clutch. Candidates include low refrigerant pressure, dirty 14-pin connection, poor connection front harness to clutch, or the clutch itself. The pair of bulbs gets two of the three most likely. To test the third, make some connectors to get the bulbs connected to the wires at the low pressure safety switch. One bulb out says you are low on refrigerant. Two out say relay. Both still lit points to 14-pin and clutch, wiring, connectors.
