lite jerking when a/c is on (96 tc)
bigc2003
09-09-2007, 05:02 PM
whats up guys. When I turn the a/c on in the car the car kind on pulles back. But this usually only happens when riding at express way speeds. When the a/c isnt on it rides fine.
09-09-2007, 10:26 PM
Working on my A/C right now.
Mine would work fine and once car got to operating temp air would start warming up.
Noticed that clutch to Compressor would stop engaging so that is why the
air was warming.
Everything was saying me air was on all the duct doors closed properly, isecond fan came on but warm air.
when it hit operating temp car would do a little lurking as you say.
Everthing checked out as far as cut off switches went.
I cut the wires at the front of compressor one purple and one black and
spliced a wire to the battery terminals and the compressor engages and runs and runs.
Today I ran it and manually cycled the clutch to get the refrigerant in an
if i could get the clutch to stay engaged i would be very happy.
i am at the conclusion that what is keeping the Compressor from engaging
is something in the Power Control Monitor.
I believe that the PCM senses something is not right in the currebt flow
or ground and panics and shuts down the compressor to conserve.
I also believe that PCM demands more juice from the alternator and works it to death.
I know that from 94 to 95 alternator was changed from 95 amp to 130 amp. i dont know what they could have added to that year that would require 33 percent more output.
i dont think they knew why it was happening or what was causing it. But a bigger alternator was their solution. I wont buy that they put the same alt as on limos because they had a lot of extra ones Im curious to see if the bigger alternator was on the vehicles that caught the cruise control on fire and began this recent recall.
I dont know if yours was recalled. But if it was and you have the 130 alt I
would suggest diconnecting the connector at the cruise control unit.
Cause if it catches fire on ya the A/C problem wont matter any more.
I wish ya luck with your situation
Mine would work fine and once car got to operating temp air would start warming up.
Noticed that clutch to Compressor would stop engaging so that is why the
air was warming.
Everything was saying me air was on all the duct doors closed properly, isecond fan came on but warm air.
when it hit operating temp car would do a little lurking as you say.
Everthing checked out as far as cut off switches went.
I cut the wires at the front of compressor one purple and one black and
spliced a wire to the battery terminals and the compressor engages and runs and runs.
Today I ran it and manually cycled the clutch to get the refrigerant in an
if i could get the clutch to stay engaged i would be very happy.
i am at the conclusion that what is keeping the Compressor from engaging
is something in the Power Control Monitor.
I believe that the PCM senses something is not right in the currebt flow
or ground and panics and shuts down the compressor to conserve.
I also believe that PCM demands more juice from the alternator and works it to death.
I know that from 94 to 95 alternator was changed from 95 amp to 130 amp. i dont know what they could have added to that year that would require 33 percent more output.
i dont think they knew why it was happening or what was causing it. But a bigger alternator was their solution. I wont buy that they put the same alt as on limos because they had a lot of extra ones Im curious to see if the bigger alternator was on the vehicles that caught the cruise control on fire and began this recent recall.
I dont know if yours was recalled. But if it was and you have the 130 alt I
would suggest diconnecting the connector at the cruise control unit.
Cause if it catches fire on ya the A/C problem wont matter any more.
I wish ya luck with your situation
Bearfoot
09-10-2007, 01:30 AM
When the A/C is running the extra HP it takes to turn the compressor on will make you feel a very light 'pull'. I seldom feel it 'release' when the compressor turns off.
09-10-2007, 06:27 PM
Cant believe it was this simple.
How I would service it again.
1 Jack up left front enough to get under.
2 Cut two wires to compressor 94 TC one prple and one blackand splice 2 ft of same size wire or larger to connector. ( Dont cut them too short)
3 Touch purple to positive and black to negative on the battery 3 seconds at a time lesve positive on battery and touch and remove ground (black wire)
Compressor should come on. If not then thats a good place to start
to getting it fixed.
OK Compressor runs. Saved yourself 200 bucks+
4 Touch and remove blackwire at 3 second intervals for 4 or 5 times.
5 Take a golf tee and place it in a rag. Remove both caps and push golf tee in the valves that look like tires stems. REAL QUICK IN AND OUT.
If you hear some air pressure that is good. System is pressurizing.
NOTE: I do not advocate the release of freon or R134A into the atmosphere.
BUT; The test releases less than trying to put more into
system even with the quick connector.
6 Remove black wire from battery and shut off car.
7 Splice purple wire back to connector and leave long black wire attached to the connector.
8 Start car and put A/C on full Blast.
9 Put black wire back on battery and compressor should start spinng
IF it spins you have an issue with the PCM. But dont sweat it
It should turn on and off every few second s
If it is CYCLING on and off you are probably all set. Your safety controls will cut power to purple if there is a problem with high pressure or low pressure thru a relay.
10 Jump in and wait for some cold air. Drive it to see if it gets really really cold.
If it is cold I am happy for you. WTG
If it is not quite cold take the hose with gauge off the can of refrigerant and close the valve like you are piercing the can. It will be closed
11 Place hose on smaller of valve stem type things start car and turn on A/C.
Pressure should built to some say 40 some say less. Mine would built to 50 then get sucked down to 20. Cans of refrigerant have 70 so I think Im alright.
If it is CYCLING at those pressures and not cold. You need some drained
and some added.
NOTE I do not advocate the release into the atmosphere. Nor oil going into the ground or sewer.
Take it somewhere and have it drained and filled by a little guy,
You know the compressor works and holds pressure by now.
Cant get TOOK there.
If it helps ya pass it on. GOOD LUCK
disconnect power to purple wire thru a relay.
Compressor runs. Cool
How I would service it again.
1 Jack up left front enough to get under.
2 Cut two wires to compressor 94 TC one prple and one blackand splice 2 ft of same size wire or larger to connector. ( Dont cut them too short)
3 Touch purple to positive and black to negative on the battery 3 seconds at a time lesve positive on battery and touch and remove ground (black wire)
Compressor should come on. If not then thats a good place to start
to getting it fixed.
OK Compressor runs. Saved yourself 200 bucks+
4 Touch and remove blackwire at 3 second intervals for 4 or 5 times.
5 Take a golf tee and place it in a rag. Remove both caps and push golf tee in the valves that look like tires stems. REAL QUICK IN AND OUT.
If you hear some air pressure that is good. System is pressurizing.
NOTE: I do not advocate the release of freon or R134A into the atmosphere.
BUT; The test releases less than trying to put more into
system even with the quick connector.
6 Remove black wire from battery and shut off car.
7 Splice purple wire back to connector and leave long black wire attached to the connector.
8 Start car and put A/C on full Blast.
9 Put black wire back on battery and compressor should start spinng
IF it spins you have an issue with the PCM. But dont sweat it
It should turn on and off every few second s
If it is CYCLING on and off you are probably all set. Your safety controls will cut power to purple if there is a problem with high pressure or low pressure thru a relay.
10 Jump in and wait for some cold air. Drive it to see if it gets really really cold.
If it is cold I am happy for you. WTG
If it is not quite cold take the hose with gauge off the can of refrigerant and close the valve like you are piercing the can. It will be closed
11 Place hose on smaller of valve stem type things start car and turn on A/C.
Pressure should built to some say 40 some say less. Mine would built to 50 then get sucked down to 20. Cans of refrigerant have 70 so I think Im alright.
If it is CYCLING at those pressures and not cold. You need some drained
and some added.
NOTE I do not advocate the release into the atmosphere. Nor oil going into the ground or sewer.
Take it somewhere and have it drained and filled by a little guy,
You know the compressor works and holds pressure by now.
Cant get TOOK there.
If it helps ya pass it on. GOOD LUCK
disconnect power to purple wire thru a relay.
Compressor runs. Cool
Automotive Network, Inc., Copyright ©2026