1995 AC help needed
Thread Starter
Racer
Joined: Apr 2009
Posts: 402
Likes: 7
From: New Tazewell Tennessee
1995 AC help needed
I can not get voltage to the compressor.....I bypassed the pressure switch and checked the fuses and checked out all the connectors. What else should I be looking at ?
Team Owner
Joined: Jul 2004
Posts: 28,367
Likes: 3,257
From: Hartford WI
When you unplug the connector to the compressor, is it getting power at all when you trigger it?
Mine was shorting out very often. Come to find out it was a wire that was grounding out because of the rubbing.
Mine was shorting out very often. Come to find out it was a wire that was grounding out because of the rubbing.
Team Owner
Joined: Jul 2004
Posts: 28,367
Likes: 3,257
From: Hartford WI
Is the relay getting power at all? I would test probe the relay and make sure it gets good power and ground and that the wire runs without a break all the way to the plug that the clutch plugs into
Team Owner
Joined: Jul 2004
Posts: 28,367
Likes: 3,257
From: Hartford WI
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Team Owner
Joined: Jul 2004
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From: Hartford WI
Burning Brakes
Joined: Feb 2009
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From: Richmond Virginia
both brown wires batt. voltage when ign. is on
green/white wire is grounded by PCM when it sees AC "request"
green wire powers AC clutch when relay is energized and working
Thread Starter
Racer
Joined: Apr 2009
Posts: 402
Likes: 7
From: New Tazewell Tennessee
thanks !
right rear of engine compartment on inner fender. it has 4 wires 2 brown--1 green and 1 green/white--It will be with other relays depending on options manual/auto trans--manual/auto climate control.
both brown wires batt. voltage when ign. is on
green/white wire is grounded by PCM when it sees AC "request"
green wire powers AC clutch when relay is energized and working
both brown wires batt. voltage when ign. is on
green/white wire is grounded by PCM when it sees AC "request"
green wire powers AC clutch when relay is energized and working
Team Owner
Joined: Jul 2004
Posts: 28,367
Likes: 3,257
From: Hartford WI
Le Mans Master
Joined: Jan 2006
Posts: 5,620
Likes: 206
From: Orlando FL
Don’t know if you have the manual or automatic (C68) system but the compressor does not have constant voltage on it. The voltage is applied to it when the compressor clutch relay is closed.
The coil of the relay is energized by the PCM in both systems. The cycling switch connects to the PCM for the signal to turn compressor on and off.
Of course some of the other electronics are different between the manual and the automatic systems.
If there is 12 volts on the clutch, it's probably bad. It can be replaced but proper spacing washers are critical. Make sure compressor is good before it's replaced.
The coil of the relay is energized by the PCM in both systems. The cycling switch connects to the PCM for the signal to turn compressor on and off.
Of course some of the other electronics are different between the manual and the automatic systems.
If there is 12 volts on the clutch, it's probably bad. It can be replaced but proper spacing washers are critical. Make sure compressor is good before it's replaced.
Last edited by pcolt94; Jun 6, 2011 at 10:14 PM.
Thread Starter
Racer
Joined: Apr 2009
Posts: 402
Likes: 7
From: New Tazewell Tennessee
thanks for the help
Don’t know if you have the manual or automatic (C68) system but the compressor does not have constant voltage on it. The voltage is applied to it when the compressor clutch relay is closed.
The coil of the relay is energized by the PCM in both systems. The cycling switch connects to the PCM for the signal to turn compressor on and off.
Of course some of the other electronics are different between the manual and the automatic systems.
If there is 12 volts on the clutch, it's probably bad. It can be replaced but proper spacing washers are critical. Make sure compressor is good before it's replaced.
The coil of the relay is energized by the PCM in both systems. The cycling switch connects to the PCM for the signal to turn compressor on and off.
Of course some of the other electronics are different between the manual and the automatic systems.
If there is 12 volts on the clutch, it's probably bad. It can be replaced but proper spacing washers are critical. Make sure compressor is good before it's replaced.
climate control system
I bypassed pressure switch. I did notice the voltage coming and going (according to the test light) even with the switch plugged up. Thats when I knew it was going to be a more expensive fix. If there are any more checks feel free to add but Im looking for a compressor with clutch. I just don't want to buy the clutch not being sure if the compressor is good or not.
Last edited by pitchadude; Jun 7, 2011 at 07:49 AM. Reason: more info
Le Mans Master
Joined: Jan 2006
Posts: 5,620
Likes: 206
From: Orlando FL
I guess test lights have their place (somewhere), but I always have used a meter having been in electronics all my life. Get a DVM and learn how to use it so you can know what's going on. A test light might not see partial voltage.
You can buy a digital for $5 today that will be just fine for checking for voltage. The bigger and better ones have bigger displays, longer leads, more durable and more scales but accuracy not a big factor for just checking for 12 volts when troubleshooting (for your needs).
If you can hand turn the compressor, then you can try the next step.
I would unplug the compressor and put battery voltage to it directly to see if the clutch will engage. This would eliminate all doubt if the clutch is good or bad. Run the engine once set up and see if the compressor will turn.
If the clutch does nothing, I don’t know if there is a way to temporally manually engage it and testing to see if the pipes get cold. Be careful if you decide to jam something in there.
You can buy a digital for $5 today that will be just fine for checking for voltage. The bigger and better ones have bigger displays, longer leads, more durable and more scales but accuracy not a big factor for just checking for 12 volts when troubleshooting (for your needs).
If you can hand turn the compressor, then you can try the next step.
I would unplug the compressor and put battery voltage to it directly to see if the clutch will engage. This would eliminate all doubt if the clutch is good or bad. Run the engine once set up and see if the compressor will turn.
If the clutch does nothing, I don’t know if there is a way to temporally manually engage it and testing to see if the pipes get cold. Be careful if you decide to jam something in there.
Last edited by pcolt94; Jun 7, 2011 at 09:54 AM.
Thread Starter
Racer
Joined: Apr 2009
Posts: 402
Likes: 7
From: New Tazewell Tennessee
meters and such
I guess test lights have their place (somewhere), but I always have used a meter having been in electronics all my life. Get a DVM and learn how to use it so you can know what's going on. A test light might not see partial voltage.
You can buy a digital for $5 today that will be just fine for checking for voltage. The bigger and better ones have bigger displays, longer leads, more durable and more scales but accuracy not a big factor for just checking for 12 volts when troubleshooting (for your needs).
If you can hand turn the compressor, then you can try the next step.
I would unplug the compressor and put battery voltage to it directly to see if the clutch will engage. This would eliminate all doubt if the clutch is good or bad. Run the engine once set up and see if the compressor will turn.
If the clutch does nothing, I don’t know if there is a way to temporally manually engage it and testing to see if the pipes get cold. Be careful if you decide to jam something in there.
You can buy a digital for $5 today that will be just fine for checking for voltage. The bigger and better ones have bigger displays, longer leads, more durable and more scales but accuracy not a big factor for just checking for 12 volts when troubleshooting (for your needs).
If you can hand turn the compressor, then you can try the next step.
I would unplug the compressor and put battery voltage to it directly to see if the clutch will engage. This would eliminate all doubt if the clutch is good or bad. Run the engine once set up and see if the compressor will turn.
If the clutch does nothing, I don’t know if there is a way to temporally manually engage it and testing to see if the pipes get cold. Be careful if you decide to jam something in there.