Free Car Repair Advice by Certified ASE Technicians
Repair Topics/ Air Conditioner-1
/ Air Conditioner-2
/ Air Conditioner-3
MORE:
Air conditioner questions
Car Air Conditioner Questions and Answers - This category
contains featured questions as examples and relate to most vehicles.
Question: 1998 Pontiac Grand Prix 3.1. It has the heavy duty cooling system
(2 fans). The AC hasn't worked in a long time and I recently discovered that the
cooling fans are not working either. I don't know how long ago they stopped working.
When I put the car in diagnostic mode, both fans come on fine. Looking at my Haynes
manual (severely lacking in electrical logic) it appears that the computer grounds
the coil on the relays to activate the fans and A/C compressor. I opened up one
relay and clipped a test wire on the computer side of the coil. As soon as I grounded
it, the AC compressor came on. I moved that relay into the other sockets for each
fan and I could turn those on as well. As best I can tell, the computer isn't getting
something it needs to turn them on. I don't feel the computer is messed up since
it will turn them on when in diagnostic mode. There are no codes on the computer.
The temp gauge works fine. I just flushed the coolant and the low coolant sensor
appears to work as well. What should I look for next and what would be the test
procedure? This is not my daily driver but will be once Firebird hibernates for
the winter.
Answer: It sounds like you have a bad
temperature switch. It is located on the lower right rear of the engine. Don't confuse
it with the temperature sensor for the computer which is located on the top rear
right of the engine.
Follow-up: Took the car in last night to get
the cooling fans fixed and replace the stolen lights. The dealer just called, here
is the deal: The fans work fine and come on at 228 degrees.... but the gauge on
the cluster reads 260 (basically pegged) at that point. The problem is the gauge
is hosed and it is $200 to whatever to get it fixed, or many much more to get it
replaced. They changed me $30 bucks to give me that information. Not too bad...
but who would have thought it was just a messed up gauge the whole time. I will
most likely install an aftermarket gauge. Thanks for all the help.
Question: 1995 Plymouth Voyager 125,000. You fellows have
a really great site! I hope you have an answer to my problem. I bought the above-mentioned
van used. About six months later, the a/c compressor quit. I replaced the whole
assembly not knowing the history of the vehicle. Upon further checking, the compressor
clutch coil had fried. This was with R-12. After replacing the whole compressor
using 134a, the van cooled fine for a couple of months. Then the coil went out again.
The compressor was still under warranty, so it was replaced. This coil lasted about
two years. About a month ago, this coil went out. It also took the clutch plate,
so I thought that maybe that was the real problem. I replaced the whole clutch assembly.
It didn't last three weeks. This time it was so bad, the compressor bearing was
in pieces when I took the assembly off. Please help if you can. This is getting
really nerve racking, not to mention expensive! The head pressures appear to be
correct. I am installing about 30 oz of 134a when I evacuate and recharge the system.
I hope this is enough info for you to give me at least an idea of where to start.
Answer: Try flushing out the entire air-conditioning system
and replacing the receiver-drier and the expansion valve.
Question: 2001 Dodge Grand Caravan LE 74,000. Hi Guys!
Interesting site here, but don't see a reference to my problem. My A/C system vents
pop over to the defrost vents when I accelerate. I went to a Chrysler dealer; they
sold me this small black vacuum reservoir to put in line with the vacuum line that
runs from the master cylinder to the control. This temporarily made a difference,
now the problem is back. I went to a salvage yard and got a large vacuum reservoir
off of an older Caravan, but this doesn't help either. I have looked at all the
vacuum lines, especially the main ones, nothing seen there. I don't have a vacuum
gauge but suspect a leak someplace. Think the control itself is a culprit? Any common
problems with this in Caravan that you know of? The dealer said they all did it.
Answer: Somewhere in the vacuum supply to the Air conditioning
controls is a check valve between the engine and the reservoir. The purpose of the
check valve is to eliminate the problem you are having. Your check valve may have
failed or you have a vacuum leak somewhere in the system.
Question: 2002 Ford Taurus mileage: 69,000. Heater is
not working. A few weeks ago, it was working fine. Now when I turn the temperature
dial from cold to hot it remains cold. I can feel the air change directions as I
change from Def. to Def & heat. Nothing is wrong with the heater core, no leaks
of any kind. Heater hose gets hot to the touch. I believe this is a vacuum or elec.
problem. Could it be a damper is not closing or opening to force the fan to blow
over the heater core vs. A/C? Not sure (can't see) where the vacuum lines are on
these newer vehicles. Do you have any suggestions?
Answer: The air-conditioning/heating controls are not
vacuum controlled but are controlled by electric motors. You may be experiencing
problems with the monitor that controls the blend door temp. Enter into diagnostic
mode to check for trouble codes.
Question: 1999 Continental, Lincoln v-6 Liter mileage:
84,000. When my compressor engages the A/C system works very well. The problem
is to get the system to engage the clutch. The vacuum motors all seem to work
appropriately. The temperature selector seems to work ok. When you vary
the temperature selector up or down the vacuum motors, doors and blower act appropriately.
The heater works ok. Every button on the control panel works, as it should.
But when the system demands cooling the compressor may or may not come on.
When you select AUTO, MAX, FLOOR/ PANEL or DEFROST the compressor may or may not
come on. The temperature setting seems to have no effect on getting the compressor
to engage. For some unknown reason and at an indeterminate point in time it
will decide to engage the clutch and the system works well for the rest of the trip.
But shut off the engine and start it again and the compressor clutch may or may
not engage. I have checked the plug-in at the clutch and when the clutch is
not engaged there is no power there. I do not know where the clutch picks
up its ground. I have found 3 grounds under the hood and they all have continuity.
When the car is not running and the ignition is off, I have removed the plug to
the clutch the plug then seems to have continuity to ground from either or the two
pins of the plug-in. This intermittent problem is driving me nuts. Do
you have any ideas? Thanks, Kevin
Answer: Yes, we just had this problem in the shop and
this is what is happening, the compressor is controlled by a pressure switch that
is on the accumulator is has electrical contacts that malfunction. Replace the low
side pressure cycling switch and retest.
Question: 1999 Honda Civic mileage: 112,000. I have
a Honda Civic 91,142 miles. My A/C works fine first time you turn it on. Runs
for 10 min then stops cooling. I got it checked out. There were no leaks
in the system. The mechanic's guess was, compressor doesn't turn on when it
is hot. He gave me an estimate of $1100 to replace the compressor, receiver
dryer, evacuate, recharge etc. Is this the only way to fix the problem?
Could it be something else that causes compressor to stop when it is hot?
I would appreciate it a lot if someone could help me out.
Answer: When the air-conditioning compressor stops working,
check the voltage to the clutch coil. If ok and the compressor is working check
the cooling fans to make sure they are on. If ok, have the refrigerant levels checked.
Question: 2004 Cadillac Deville 5.2 mileage: 40,000.
I have a very strange electrical problem. The A/C blower fan continues to
run at high speed even when the Air Conditioner / Heater control is turned off,
and more importantly, even when the ignition switch is turned to the off position.
Any suggestions?
Answer: The blower motor is controlled by a speed control
module that is probably shorted "on" causing the blower to run all the time.
Replacing it should fix your problem.
Question: 1999 Mazda RX7 54,000. My car makes this
loud squealing noise when I start it and then it stops. I was told it was my air
conditioner belt, but I had it looked at and it wasn't worn so they put some belt
dressing on it and it stopped, for awhile. Now it's squealing even worst even
when I'm just stopping at a red light. What should I do?
Answer: You will probably have to replace the air-conditioner
belt. Once a belt starts to squeal the sides of the belt glaze over and no
adjusting or treatment will permanently stop the squealing.
Question: 1998 Ford Probe mileage: 75,000. I live
in Minnesota where you don't use the air conditioner during the summer.
Last week it finally got warm enough. When I try to activate it nothing happens.
Well, something does happen. If the car is at idle, it will rev up slightly
as if the car is expecting to be bogged down. That's it. I don't hear
the compressor engage and I don't hear the engine bog down. I've checked the
fuses. The AC was working fine last summer. I'm willing to have it looked
at by a professional, but want to exhaust my own options first.
Answer: Your air-conditioning system may be low on refrigerant.
The compressor will not engage if the system is low on refrigerant due to the low-pressure
cut-off switch.
MORE:
Air conditioner questions
Repair Topics /
Air Conditioner-1
/ Air Conditioner-2
/ Air Conditioner-3
Look up more air conditioner questions in our
Car Repair forum section.
Got Car Repair Questions? we
will answer it for free.
Related Subjects
GET ONLINE
CAR REPAIR MANUALS. Get instant access
to your vehicles drive belt routing, wiring diagrams, trouble code information,
updates and factory bulletins.
| 
