ac works, ac doesn't work
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Fleet Owner
Joined: Aug 2004
Posts: 20,418
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From: AZ
ac works, ac doesn't work
When clutch is engaged you can hang a side of beef in there. Then, it stops engaging and if I wiggle the wires on the top of compressor, the clutch will engage again. The plug-in on top, by the clutch, is the power, isn't it? Once or twice when I wiggled it the clutch would engage. The plug-in in the middle top of the compressor seems to be the problem, but I don't know. When I wiggle those wires and hold them in a certain position the clutch stays engaged, for a while. Is this a sensor that might be bad and needs replaced? Or, do I just have a wiring problem? Any help will be appreciated! Thanks
Fleet Mechanic
Joined: Feb 2006
Posts: 1,776
Likes: 5
From: Lorain County, Ohio
That's the connection for the clutch coil. The first thing to do would be to clean the terminals in both halves of the connector. Use a pick to tighten the terminals in the harness side. If it still has problems, there could be a bad connection inside the coil.
Also, check the clutch gap. If the connector has resistance and the gap is a bit too wide, the coil won't be able to pull the clutch in . If the gap is .025" or wider, it needs to be adjusted.
Also, check the clutch gap. If the connector has resistance and the gap is a bit too wide, the coil won't be able to pull the clutch in . If the gap is .025" or wider, it needs to be adjusted.
Thread Starter
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Fleet Owner
Joined: Aug 2004
Posts: 20,418
Likes: 197
From: AZ
That's the connection for the clutch coil. The first thing to do would be to clean the terminals in both halves of the connector. Use a pick to tighten the terminals in the harness side. If it still has problems, there could be a bad connection inside the coil.
Also, check the clutch gap. If the connector has resistance and the gap is a bit too wide, the coil won't be able to pull the clutch in . If the gap is .025" or wider, it needs to be adjusted.
Also, check the clutch gap. If the connector has resistance and the gap is a bit too wide, the coil won't be able to pull the clutch in . If the gap is .025" or wider, it needs to be adjusted.
Fleet Mechanic
Joined: Feb 2006
Posts: 1,776
Likes: 5
From: Lorain County, Ohio
I was referring to the connector by the clutch. If you meant the connector toward the rear of the compressor, that's the high pressure cutout switch. Either way, clean the connector and tighten the terminals first. The HPCO is replaceable if necessary.
The "clutch gap" is measured between the clutch plate (the part that spins when the compressor is engaged) and the pulley (The part that spins with the belt). You adjust the gap by removing the center bolt in the clutch plate, removing the plate and adding or subtracting shim washers.
The "clutch gap" is measured between the clutch plate (the part that spins when the compressor is engaged) and the pulley (The part that spins with the belt). You adjust the gap by removing the center bolt in the clutch plate, removing the plate and adding or subtracting shim washers.
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Fleet Owner
Joined: Aug 2004
Posts: 20,418
Likes: 197
From: AZ
lsrx101, Thanks a awful lot for that explanation. Today I cleaned both plug-ins and the ac didn't quit on me but I only drove it a few miles. If it acts up again I'll check the gap. Two more questions if I can bother you, if I do have to replace the HPCO, it doesn't let out the coolant, does it? When I put the gauges on it today, I had 40 low and 200 high. I heard its suppose to be 30 low side and between 150 & 200 high side. If I have to let out some coolant, do you do it on the low or high side? Thanks again, Glenn
Fleet Mechanic
Joined: Feb 2006
Posts: 1,776
Likes: 5
From: Lorain County, Ohio
The basic rule of thumb for the pressures is:
High- 2.5 times the ambient temperature (200@80degrees...)@ 1500RPM.
Low- about 25-28 @ 1500RPM
Those are just ballpark figures as the actual readings will vary with humidity, underhood temp, fan setting, sun load, etc.
Put the AC on MAX, high blower, doors open, engine at 1500Rpm then post your readings. If the outlet air is "like a meat locker" as you stated earlier, you are probably ok.
If the problem persists:
-Check the clutch gap. It's free and simple to do.
-If the low side pressure drops below 25psi and the compressor quits-likely the low pressure switch on the accumulator
-If the high side pressure climbs over 300psi and the compressor quits- likely the fan clutch.
-If the pressures are normal and the compressor quits- likely the high or low side pressure switch is failing. Electrical tesdting is needed.
Both of the switches can be replaced without losing refrigerant. There are schrader valves under them.
Since you have a gauge set but are unsure how to interpret the pressures,consider buying this book:Automotive Air Conditioning Parts & Equipment - ACKITS.COM: Mastercool Auto AC Repair Manual Lots of good info.
High- 2.5 times the ambient temperature (200@80degrees...)@ 1500RPM.
Low- about 25-28 @ 1500RPM
Those are just ballpark figures as the actual readings will vary with humidity, underhood temp, fan setting, sun load, etc.
Put the AC on MAX, high blower, doors open, engine at 1500Rpm then post your readings. If the outlet air is "like a meat locker" as you stated earlier, you are probably ok.
If the problem persists:
-Check the clutch gap. It's free and simple to do.
-If the low side pressure drops below 25psi and the compressor quits-likely the low pressure switch on the accumulator
-If the high side pressure climbs over 300psi and the compressor quits- likely the fan clutch.
-If the pressures are normal and the compressor quits- likely the high or low side pressure switch is failing. Electrical tesdting is needed.
Both of the switches can be replaced without losing refrigerant. There are schrader valves under them.
Since you have a gauge set but are unsure how to interpret the pressures,consider buying this book:Automotive Air Conditioning Parts & Equipment - ACKITS.COM: Mastercool Auto AC Repair Manual Lots of good info.
Hotshot
Joined: Jan 2004
Posts: 19,760
Likes: 1,079
From: St Louis
Leave the refrigerant alone. Unless it was overcharged by someone who didn't know what they were doing, it is extremely unlikely it is overcharged, especially since you indicate that the system performs very well.
Both the HPCO and the cycling switches have Schreader valves under them. You won't lose more than a minute amount of refrigerant.
Note: Pressure readings must be take in context, specifically, ambient temperature, relative humidity, blower speed, engine RPM, etc, etc...
Steve
Both the HPCO and the cycling switches have Schreader valves under them. You won't lose more than a minute amount of refrigerant.
Note: Pressure readings must be take in context, specifically, ambient temperature, relative humidity, blower speed, engine RPM, etc, etc...
Steve
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