A/C Question
06-30-11, 07:37 PM
#1
Coolant Leak
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Location: Dallas, TX
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A/C Question
Hey guys sorry to start another AC thread but I searched and didn't find exactly what I was looking for.
My AC never worked and last year I got some R12 and took it to a shop to get charged to see what would happen. Turned out it was converted to r134 a while back so the shop charged it up and it worked great. Lasted me all last year and then this summer the compressor was intermittent. Somedays it wouldn't cycle on until eventually it didn't kick on at all. So I thought it must have all leaked out. I took it to get recharged and it was still half full.
So my problem is that the compressor isn't kicking on... Where should I start to problem solve this?
My AC never worked and last year I got some R12 and took it to a shop to get charged to see what would happen. Turned out it was converted to r134 a while back so the shop charged it up and it worked great. Lasted me all last year and then this summer the compressor was intermittent. Somedays it wouldn't cycle on until eventually it didn't kick on at all. So I thought it must have all leaked out. I took it to get recharged and it was still half full.
So my problem is that the compressor isn't kicking on... Where should I start to problem solve this?
06-30-11, 07:49 PM
#2
There's a pressure switch in (I THINK) the high side line that will prevent the compressor from kicking on if the pressure is too low. So even though it was still half full, the pressure may not have been enough to allow the compressor clutch to engage. You need to shoot some UV dye and fill it back up with the proper amount of refrigerant before continuing. Otherwise, you're killing our atmosphere by continually recharging your ac. 
(Hypocritical, I know. We all drive rotary-powered cars...)
(Hypocritical, I know. We all drive rotary-powered cars...)
06-30-11, 08:02 PM
#4
Ok.... Then, take a look at this diagram:
http://www.rotaryheads.com/PDF/2nd_g...ng_diagram.pdf
page 57, bottom right corner. You see there's a pressure switch, a thermostat, and it feeds that info to the ecu. What's probably going to be easiest at this point would be this: If you know where your compressor is, look for the wire coming off it. It should be a single wire with a connector. Unplug the connector and stick a voltmeter on the harness side. Start the car and turn the AC on. If it's reading 12v, then either the compressor or clutch is possibly bad. Did the belt squeal any when you had it running?
http://www.rotaryheads.com/PDF/2nd_g...ng_diagram.pdf
page 57, bottom right corner. You see there's a pressure switch, a thermostat, and it feeds that info to the ecu. What's probably going to be easiest at this point would be this: If you know where your compressor is, look for the wire coming off it. It should be a single wire with a connector. Unplug the connector and stick a voltmeter on the harness side. Start the car and turn the AC on. If it's reading 12v, then either the compressor or clutch is possibly bad. Did the belt squeal any when you had it running?
06-30-11, 08:23 PM
#5
Also check the 10 amp Cigar fuse as well as the 15 amp Wiper fuse.
Pin 1O at the ECU needs to show less than 2.5 volts at idle w/AC switch on as well as the blower too, and idling w/AC off and blower on the voltage should be 12 volts.
Pin 1L (AC Relay) should show less than 2.5 volts w/AC on, ignition to on and blower on. With AC off and ignition and blower on it should read 12 volts.
Pin 1O at the ECU needs to show less than 2.5 volts at idle w/AC switch on as well as the blower too, and idling w/AC off and blower on the voltage should be 12 volts.
Pin 1L (AC Relay) should show less than 2.5 volts w/AC on, ignition to on and blower on. With AC off and ignition and blower on it should read 12 volts.
06-30-11, 09:39 PM
#6
grab the compressor clutch and spin it (engine off) if it spins your ok. the compressor is not locked up.
take a jumper wire and jump the pressure switch with the a/c on if the compressor clicks on its the pressure switch. if not trace the 12 volts from the relay to the compressor if thats all good. trace the signal wire from the a/c control unit to the relay.
Just study the wiring diagram and follow the power wire to the clutch. the older a/c systems are easier to diag. than the new cars.
take a jumper wire and jump the pressure switch with the a/c on if the compressor clicks on its the pressure switch. if not trace the 12 volts from the relay to the compressor if thats all good. trace the signal wire from the a/c control unit to the relay.
Just study the wiring diagram and follow the power wire to the clutch. the older a/c systems are easier to diag. than the new cars.
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