Compressor not getting power...help
#1
02-23-2011, 06:46 PM
Compressor not getting power...help
I'm trying to fix a friends 96 Accord 25th Anniversary Edition.
The A/C is not working and the compressor is not getting power, specifically the single black wire leading to the compressor is not getting 12v. The relay is getting power so I assumed the relay went bad and replaced it today...still no power going to the compressor. I manually powered the black wire with 12v from the battery and the clutch engaged but the A/C never got cold. From this I am thinking it is possible the system has no freon and a low pressure switch is keeping the compressor from turning on, but don't they usually quickly cycle on and off in this situation? And in this situation wouldn't the black wire leading to the compressor still get 12v and the pressure switch would internally cut power to the clutch?
I'm pretty lost here, any suggestion guys?
The A/C is not working and the compressor is not getting power, specifically the single black wire leading to the compressor is not getting 12v. The relay is getting power so I assumed the relay went bad and replaced it today...still no power going to the compressor. I manually powered the black wire with 12v from the battery and the clutch engaged but the A/C never got cold. From this I am thinking it is possible the system has no freon and a low pressure switch is keeping the compressor from turning on, but don't they usually quickly cycle on and off in this situation? And in this situation wouldn't the black wire leading to the compressor still get 12v and the pressure switch would internally cut power to the clutch?
I'm pretty lost here, any suggestion guys?
#2
02-23-2011, 06:59 PM
The pressure switch is not part of the compressor. It is on the a/c hose in the area under the battery. If the pressure is low, it cuts power to the a/c thermostat. I also think the ECU can detect if the pressure switch is open/closed.
The wire color that goes to the compressor should be red, so inspect the wiring between the compressor and relay for shoddy repair work.
You can unplug the pressure switch and jump the connector with a piece of wire. Use a volt meter to see if you get 12V on the wire to the compressor. I wouldn't run the compressor without any freon in the system.
Since the compressor was running and you had no cold air, I would suspect that there is a leak somewhere. You should test the system pressure. I'm not sure if you have a manifold to do the testing yourself.
The wire color that goes to the compressor should be red, so inspect the wiring between the compressor and relay for shoddy repair work.
You can unplug the pressure switch and jump the connector with a piece of wire. Use a volt meter to see if you get 12V on the wire to the compressor. I wouldn't run the compressor without any freon in the system.
Since the compressor was running and you had no cold air, I would suspect that there is a leak somewhere. You should test the system pressure. I'm not sure if you have a manifold to do the testing yourself.
#3
02-23-2011, 07:05 PM
You're on the trail. Suggest downloading the 94-97 Accord Manual from Online Manuals links in DIY forum.
The ECU enables the relay to couple 12V to compressor through the AC relay. If AC pressure switch is open, the ECU receives a signal that tells it to disable the AC relay.
You can jumper the switch and force compressor to run. Not very long or compressor may sieze due to lack of lubrication (no R134a to carry lubricant).
Check compressor shaft seal, hose crimps, connections for evidence of leaking (oily/dirty stains).
good luck
The ECU enables the relay to couple 12V to compressor through the AC relay. If AC pressure switch is open, the ECU receives a signal that tells it to disable the AC relay.
You can jumper the switch and force compressor to run. Not very long or compressor may sieze due to lack of lubrication (no R134a to carry lubricant).
Check compressor shaft seal, hose crimps, connections for evidence of leaking (oily/dirty stains).
good luck
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