Would this bare wire shut down the ac system?
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NoSlo
SHO Owner
It should continue to work if the wires are not broken, but dangerous if something shorts them to ground.
Chances are like 99% the original R12 coolant leaked out some time in the last 25 years, and you will need to replace all the o-rings, get a new accumulator/dryer and orifice tube, flush the compressor, condenser, and evaporator, and recharge with r134a coolant.
Chances are like 99% the original R12 coolant leaked out some time in the last 25 years, and you will need to replace all the o-rings, get a new accumulator/dryer and orifice tube, flush the compressor, condenser, and evaporator, and recharge with r134a coolant.
NoSlo
SHO Owner
The clutch cycling pressure switch is mounted on a Schrader valve-type fitting on the top of the suction accumulator/drier assembly. A valve depressor, located inside the threaded end of the pressure switch, presses in on the Schrader valve stem as the switch is mounted and allows the suction pressure inside the accumulator/drier canister to act on the switch. The electrical switch contacts will open when the suction pressure drops to 22 to 28 psi on R-12 systems, 22-25 psi on R-134a systems. The contacts will close when the suction pressure increases to 40-47 psi on R-12 systems and 39-47.5 on R-134a systems.
Ambient temperatures below approximately 45-50°F during cold weather seasons will prevent the pressure switch contacts form closing. This is due to the pressure/temperature relationship of the refrigerant and the requirement of the system pressure to reach the pressure required psi to close the switch contacts. The switch contacts control the electrical circuit to the compressor magnetic clutch coil. When the switch contacts close, the signal to energize the A/C clutch is sent to the Constant Control Relay Module (CCRM). The CCRM then supplies the voltage to energize the magnetic clutch for compressor operation. When the pressure switch contacts open, the CCRM opens the clutch electrical circuit to de-energize the clutch and compressor operation stops. The clutch cycling pressure switch, when functioning properly, will control the evaporator core pressure at a point where the plate/fin surface temperature will be maintained slightly above freezing which prevents evaporator icing and the blockage of airflow.
When the entire system is under-pressurized from a lack of refrigerant, the electrical contacts of the pressure switch never close, and no electricity will pass. This disables the air conditioning system completely, and just as effectively as unplugging the harness connector from the pressure switch.
Ambient temperatures below approximately 45-50°F during cold weather seasons will prevent the pressure switch contacts form closing. This is due to the pressure/temperature relationship of the refrigerant and the requirement of the system pressure to reach the pressure required psi to close the switch contacts. The switch contacts control the electrical circuit to the compressor magnetic clutch coil. When the switch contacts close, the signal to energize the A/C clutch is sent to the Constant Control Relay Module (CCRM). The CCRM then supplies the voltage to energize the magnetic clutch for compressor operation. When the pressure switch contacts open, the CCRM opens the clutch electrical circuit to de-energize the clutch and compressor operation stops. The clutch cycling pressure switch, when functioning properly, will control the evaporator core pressure at a point where the plate/fin surface temperature will be maintained slightly above freezing which prevents evaporator icing and the blockage of airflow.
When the entire system is under-pressurized from a lack of refrigerant, the electrical contacts of the pressure switch never close, and no electricity will pass. This disables the air conditioning system completely, and just as effectively as unplugging the harness connector from the pressure switch.
so you can test the compressor and clutch by taking off the connector from the a/c cycling switch and jumpering the connector. when you do this and turn on the a/c, the clutch should kick in and the compressor run as well as the cooling fans should come on. don't run it for more than 15-20 seconds in that configuration or you could seize the compressor from lack of ****.
if the system passes the test above, then you just need to find the leak, fix it, and recharge the system. you can still get the R134a conversion stuff - that is what I would do.
if the system passes the test above, then you just need to find the leak, fix it, and recharge the system. you can still get the R134a conversion stuff - that is what I would do.
luigisho
SHO Member
I haven't seen a normally driven and operated car have a compressor last 25yrs on the original. I'm sure someone may have found an exception somewhere but I have not witnessed this outside a low mile well cared for car. You may or may not have the original still on that car. The clutch will not engage if the gap is too large from excessive wear and from not enough pressure in the system to activate the clutch. Try for cheaper fixes as mentioned above. If those don't work you would have to invest some dollars to get it back up to par.
NoSlo
SHO Owner
280k miles on mine (although the pulley broke)
NoSlo
SHO Owner
If you jumper the switch to test, the EATC will still need to be put in a mode that would turn on the AC system, such as "max ac", and the vehicle running.
most likely. now, with the engine off try to rotate the a/c clutch to see if you can turn over the a/c compressor at all. if it turns over okay by hand, there is a slight possibility that by adding oil and refrigerant you can get it to work, but in my experience even if you get it to work for a while the compressor will lock up within a year. so, my advice would be to find a new/used compressor and change it. you will also want to take off each of the lines and have them cleaned to get any debris out of them that may have been generated by the failing compressor. you will need to do this yourself or it will cost you more than the car is worth...
NoSlo
SHO Owner
I would suspect that the screech is due to lack of compressor coolant charge and oil lubricant. It could also be the not-recently exercised clutches slipping from contamination, rust, or increased load from the un-lubricated compressor. You confirmed that the clutch circuit operates though.
Since we know the AC system never turns on from the pressure switch never being activated (and that's assuming it was tested in normal ambient temperature or with the engine bay warmed up), we know the primary fault in the system is lack of pressure or pressure switch input, usually from one of a dozen 25 year old o-rings failing. This can be confirmed with a pressure measurement using a high-pressure tire gauge. The AC compressor, while obviously not brand new, would have been operating correctly up until the point that leakage caused pressure less than allowed for cycling operation.
The compressor will need to be removed, have oil dumped out and an air or nitrogen flush and new PAG oil worked in anyway, and the hand feel at that time can determine the condition.
I have a used 10P15F compressor off a r134a year car (which donated its pulley) if you want to replace it anyway.
Since we know the AC system never turns on from the pressure switch never being activated (and that's assuming it was tested in normal ambient temperature or with the engine bay warmed up), we know the primary fault in the system is lack of pressure or pressure switch input, usually from one of a dozen 25 year old o-rings failing. This can be confirmed with a pressure measurement using a high-pressure tire gauge. The AC compressor, while obviously not brand new, would have been operating correctly up until the point that leakage caused pressure less than allowed for cycling operation.
The compressor will need to be removed, have oil dumped out and an air or nitrogen flush and new PAG oil worked in anyway, and the hand feel at that time can determine the condition.
I have a used 10P15F compressor off a r134a year car (which donated its pulley) if you want to replace it anyway.
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Thanks for all of the great advice, input, and heads up. The shoforum is truly an amazing resource and community.
So. .. how much In over my head... am I getting into here. Everything I know about under the hood I learned right HERE. I have never learned auto mechanics, etc. I DID change out my waterpump in my gen. 1 years ago... through the help of some of the great people here.
Like ruby said, if I don't do it myself, I will have more in the ac repair than the car is worth. ..
Is this even possible by one such as me?
So. .. how much In over my head... am I getting into here. Everything I know about under the hood I learned right HERE. I have never learned auto mechanics, etc. I DID change out my waterpump in my gen. 1 years ago... through the help of some of the great people here.
Like ruby said, if I don't do it myself, I will have more in the ac repair than the car is worth. ..
Is this even possible by one such as me?
luigisho
SHO Member
Possible but as with alot of learning curves you have to accept the you may do it wrong or break something along the way. Auto repair tuition isn't always free. Any large scale repair may be more than the car is worth at this point. Suspension overhaul, a/c overhaul, etc. You have to evaluate if it is worth it for you every time and compare that to the cost of another vehicle at whatever price point and what might be lurking there. Hard to find a 'cheap car' that doesn't need a good bit of work
Most of the old school guys that I knew that insisted on driving really cheap cars adjusted themselves to used tires, creaky worn suspension, headliner a mess etc. and just didn't care about making it whole again. When that one got too far gone they dumped it and went to the next one. It's about your personal approach to what you drive. Keep in mind they would go without ac in the summer and it's hot and humid over here. They don't pay it any mind
Most of the old school guys that I knew that insisted on driving really cheap cars adjusted themselves to used tires, creaky worn suspension, headliner a mess etc. and just didn't care about making it whole again. When that one got too far gone they dumped it and went to the next one. It's about your personal approach to what you drive. Keep in mind they would go without ac in the summer and it's hot and humid over here. They don't pay it any mind
Yes, you can do it yourself, for the most part. Once you replace the various parts, you will need to have a vacuum pulled on the system, and you may decide to pay someone to do that since the cost of the compressor to do it is relatively high. However, if you buy the compressor and do it yourself and discover that you still have a leak, then you can fix that leak and pull a vacuum again for no additional cost, whereas if you are paying someone to vacuum it down, you will have to pay each time. Since the car is old and its your first time doing this, there is a good chance you will not get all the leaks sealed on your first try, so take that into consideration as you plan your tactics.
The good news about the internet is there are tutorials and videos of "how to" all over, and the a/c system on virtually any Ford is the same conceptually, so you can get a pretty good education before you start.
The good news about the internet is there are tutorials and videos of "how to" all over, and the a/c system on virtually any Ford is the same conceptually, so you can get a pretty good education before you start.
So I looked on rock auto. .. looks like around $150 would get both lines, condenser, accumulator/drier. Wouldn't that make the most sense? Or is that overkill? What other essentials are needed for an overhaul? Are o rings included with those parts?
then you also need a different compressor. and you will need to flush out the condenser and evaporator.
usually the o-rings are included in those items, but it sometimes depends on what brand the parts are. if missing, you can get them at a local auto parts store, usually as part of a kit that has way more than you need.
you are on the right track to do it the correct way.
usually the o-rings are included in those items, but it sometimes depends on what brand the parts are. if missing, you can get them at a local auto parts store, usually as part of a kit that has way more than you need.
you are on the right track to do it the correct way.
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