Diagnosing the A/C
#1
Diagnosing the A/C
I put a belt on the 22re to see where I stand with the A/C, started it up and I have nothing. The light comes on but the clutch is not engaging.
I have NO IDEA of how to troubleshoot the system. Could someone give me an idea where to start and in what order? I have someone coming by possibly tomorow to put guages on it but I'm not sure how proficient he is at it himself.
Any help would be great.
Thanks
Larry
I have NO IDEA of how to troubleshoot the system. Could someone give me an idea where to start and in what order? I have someone coming by possibly tomorow to put guages on it but I'm not sure how proficient he is at it himself.
Any help would be great.
Thanks
Larry
#2
Registered User
iTrader: (1)
Step one would be to see if you do indeed have the vehicle voltage to the compressor just because the light comes on does not mean it is at the compressor.
It might be it is just unplugged.
At that point you can jumper battery voltage to the compressor and see if the clutch pulls in telling you it does work or not. Do you just replace clutch hoping the compressor is good???
This could get very expensive!!!
Once the clutch has been R&R it is time to see if the compressor works hook up your gauges see what you have if anything.
If nothing pull a vacuum and see if it holds most manuals say 24 hours but I doubt many do it that long
Without a vacuum pump it is sort of a waste of time unless you just need to top off a known good system.
Check for leaks if there are any in the evap coil it is a major pain to see let alone replace.
Any shop that does ac work must check for and repair any leaks before your system is charged or so people tell me here in Pa
That should get you started
It might be it is just unplugged.
At that point you can jumper battery voltage to the compressor and see if the clutch pulls in telling you it does work or not. Do you just replace clutch hoping the compressor is good???
This could get very expensive!!!
Once the clutch has been R&R it is time to see if the compressor works hook up your gauges see what you have if anything.
If nothing pull a vacuum and see if it holds most manuals say 24 hours but I doubt many do it that long
Without a vacuum pump it is sort of a waste of time unless you just need to top off a known good system.
Check for leaks if there are any in the evap coil it is a major pain to see let alone replace.
Any shop that does ac work must check for and repair any leaks before your system is charged or so people tell me here in Pa
That should get you started
#3
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the most common problem you're gonna run into is that the refrigerant level is low, or flat out empty. because of this the low pressure switch isn't going to allow the compressor to turn on, and you will have no voltage to the compressor. You might not want to hear it, but the best starting point is to take it to a shop and have them do an evac/recharge on the system. they can tell you how much refrigerant came out of the system to indicate if you have a leak or not, and charge it up giving you a better starting point. you may have further problems after this though. if you jump 12 volts to the compressor, sure it will run if its not faulty, but if there isn't enough oil in the system you can damage the compressor, so i would advise against that until you know the system is fully charged and has oil. now, if you still have an r-12 equipped ride, you might as well just go ahead and convert over to r-134. just had to convert mine over. all i did was suck out the r-12, put the r-134 fittings on, charged it up, and it blows cold as ever. good luck!
#4
Registered User
Turn the litlle knob on your a/c amplifier behind the globe box to see if the compressor clutch kicks in, but make sure you have freon in the system. I went to 134a refrigerant and the comp. clutch was not kicking until I turn the knob behind the globe box and it did, now it's blowing nice and cold.
#5
Registered User
iTrader: (3)
Ok, i'll ask the obvious question:
what year is your vehicle?????
That would go along ways in helping you.
FIRST THING- put gauges on it to see if it has any pressure. If there's significant pressure (roughly 1lb of pressure for every 1degree of ambient temp), then test for power at the compressor. Then move back from there. could be a low pressure cut out switch, A/C amplifier issue, wiring, etc, etc, etc ad-nauseum!
If there is no pressure the system has to be pressure tested (nitrogen works well) to see if it holds.
IF the system hasnt been working in a while, I HIGHLY recommend replacing all the orings, the receiver/dryer, the metering device (orifice tube or expansion valve) and oil in the compressor. Check the FSM for proper oil/refrigerant charge adn pull a DEEP vacuum on the system before recharging- the point here is moisture removal as water boils at room temp (at sea level) in a deep vacuum.
If its older, i'd replace the Shrader valves too (where the gauges connect).
what year is your vehicle?????
That would go along ways in helping you.
FIRST THING- put gauges on it to see if it has any pressure. If there's significant pressure (roughly 1lb of pressure for every 1degree of ambient temp), then test for power at the compressor. Then move back from there. could be a low pressure cut out switch, A/C amplifier issue, wiring, etc, etc, etc ad-nauseum!
If there is no pressure the system has to be pressure tested (nitrogen works well) to see if it holds.
IF the system hasnt been working in a while, I HIGHLY recommend replacing all the orings, the receiver/dryer, the metering device (orifice tube or expansion valve) and oil in the compressor. Check the FSM for proper oil/refrigerant charge adn pull a DEEP vacuum on the system before recharging- the point here is moisture removal as water boils at room temp (at sea level) in a deep vacuum.
If its older, i'd replace the Shrader valves too (where the gauges connect).
#7
Registered User
The clutch wont engage when the refrigerant is low or empty, otherwise if there's a leak it will just pumP it into the atmosphere, a good way to check at home is just hook up a compressor and see if you can hear any leaks, start at 30psi and increase to see if you can hear anything, if not keep and eye on he pressure gauge, if it goes down then you have a slow leak
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#8
Registered User
A good chunk of my 'no ac' problems (especially in the spring of the year) is a stuck low pressure switch. After a few winter months of no AC activity the low pressure switch will stick. Engage the AC and using a screwdriver, tap on the low pressure switch and see if the AC clutch will engage.
If this works it does not mean the low pressure switch is bad, only needs to work a little bit.
For educational reasons, the high side is the small pipe, low side is the large pipe.
If this doesnt work and you have voltage in the system, more than likely you have low charge in the system. If you charge it, make sure to have a sniffer on hand as you will have a leak somewhere.
If this works it does not mean the low pressure switch is bad, only needs to work a little bit.
For educational reasons, the high side is the small pipe, low side is the large pipe.
If this doesnt work and you have voltage in the system, more than likely you have low charge in the system. If you charge it, make sure to have a sniffer on hand as you will have a leak somewhere.
#9
Registered User
iTrader: (3)
This is why I suggested using DRY OIL FREE Nitrogen.
As I said earlier:
"there are 2 ways to do any A/C job- the right way and ALL THE OTHER WAYS"
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