Strange A/C Issue

[ELM'sLX+CHL'sDX]

Hey Guys,

My A/C has been acting funny lately. It works great while the car is not moving. But as soon as you start driving, the air becomes warmer (often just as if you had the vents blowing full-blast with the A/C off). I've tried just reving the engine to 3 rpm while remaining still and the A/C is still perfectly cold. It is only when the car is in motion that this problem occurs.

Has anyone had a similar problem? Any ideas on what this might be?

Erika

[Morpheus]

Bah, just cut the belt and pull it out.

I'd bring it to a mechanic, its a pain to deal with yourself and I think its kinda dangerous and illegal to mess with A/C

[sharpshooter]

Another problem it could be is that your A/C system does not have enough fluid. that was the problem with my A/C system untill I converted it to 134 coolent you can buy a kit that comes with adapters and coolent. but you have to take it to a macanic that can safely remove your old R 12 coolent. it was about $15 to get it done.

PS. my A/C system works great after switching.

[wthramann]

This may sound silly but I am trying to think of what is different when you are moving vs. stationary. There is air flow from the front to the rear of the car while moving. The condenser fan blows air out of or into the engine compartment? Logically it would draw air in to augment the flow from movement. Could the polarity of the wires be off? I would check the condenser in front of the radiator to make sure there are no obstructions. Be sure both fans are on with the A/C on.

[SiR]

Originally posted by ELM'sLX+CHL'sDX
Hey Guys,

My A/C has been acting funny lately. It works great while the car is not moving. But as soon as you start driving, the air becomes warmer (often just as if you had the vents blowing full-blast with the A/C off). I've tried just reving the engine to 3 rpm while remaining still and the A/C is still perfectly cold. It is only when the car is in motion that this problem occurs.

It might be that the belt is loose. Just give the A/C belt a nice push or pull to see how loose it is. It might be fine idling cuz its not rotating a lot. But until you start driving and the engine revs higher, the belt might be loose enough that it starts slipping. But you just said that reving it to 3k, its still cold. Weird...

My bet is the belt is loose.

[ELM'sLX+CHL'sDX]

After further investigation into my strange A/C issue, I have more strange symptoms to report:

I've found that the compressor will only switch on once the auxiliary fans are already running (such as when the car is at a standstill). When the A/C does switch on, it works perfectly (all fans and compressor running). If the auxiliary fans are not already running, turning on the A/C switch will neither start the compressor nor the fans.

As a little experiment, I've been driving around all weekend with the A/C switch in the on position just to see when the compressor will turn on. Sure enough, when I first start running the car and am running on city streets, the auxiliary fans are on and I can run the A/C perfectly. However, as soon as I get on the freeway and the auxiliary fans turn off (because there's enough air flowing through the radiator), the compressor turns off as well. Once I get off the freeway and say stop at a red light, the auxiliary fans kick back on and so does the compressor.

It is very puzzing to me why the act of turning on the A/C is not itself enough to turn on the fans and compressor. Obviously the fans and compressor are fully operational, but there is some electrical problem preventing the A/C from turning on when the auxiliary fans are not independently running.

Any ideas?

Erika

[SiR]

Oh oh... Its gone down to electrical, the most hated systems!!!

The fans must be on at all times no matter what when the A/C switch is on. Im guessing that the fuses and relays are all good.

[wthramann]

From the service manual 23-8, Troubleshooting Flow Chart-A/C Clutch and Both Cooling Fans Do Not Come On

Test Diode, Pressure Switch, thermostat, A/C switch, Heater(Blower) Fan switch.

I started typing in all the steps to perform these tests but then realised you might not want to do all of this. Also this may have already been uploaded in the how to section.

[Techno]

Sounds like someone else before you wired it wrong. I would make sure that the wires are not linked to the fan relay. It sounds like the compressor clutch wire is wired into the power wire for the cooling fans. You might have to get some help wiring it correctly

Techno

[ELM'sLX+CHL'sDX]

Originally posted by Techno
Sounds like someone else before you wired it wrong. I would make sure that the wires are not linked to the fan relay. It sounds like the compressor clutch wire is wired into the power wire for the cooling fans. You might have to get some help wiring it correctly

Techno

One thing I'm pretty sure of is that the A/C is wired correctly. The original owner of the car only had it dealer serviced. I'm the second owner and I've had the car for 3 1/2 years. I've never changed anything with the A/C or any wiring in the car whatsoever for that matter. The A/C has always worked fine up until now so I definitely suspect that the problem is an electrical part that has gone bad (as opposed to incorrect wiring).

I have a copy of the Honda Service Manual so I'm going to try to complete some of the troubleshooting steps. It's troublesome though, because looking over the service manual, they have all these flowcharts to follow depending on whether the compressor and/or one or both of the rans is running. Well in my case, they all run fine, just as long as the auxiliary fans come on first. So I don't really know what chart applies.



Erika

[wthramann]

From reading other posts about electrical problems it is usually the ground that is the fault. The temperature sensor may provide an alternative ground source when it is closed. If you study the electrical circuit diagrams you will see the temperature sensor has a different ground. This would explain why the A/C works when the cooling fans are on. Use the flow chart A/C Clutch and Both Cooling Fans Do Not Come On. Good luck.

[njpeter]

I'll agreeez..some electrical problem...could be as simple as a bad connection on the HP switch..if the motor rocks alot when in gear, it _could_ cause the fault..at idle..no problem...try R with the brakes on hard...and by all means get a guage on the a/c to check pressures if the wiring idea pans out.

[doug]

you might just need to get a charge and add some oil. the reason is that if system pressure is below 30 psi there is a switch to cut off the compressor to keep from self destructing due to lack of coolant and/or oil. if it were me I would have the system vacuumed by a pro and then do a charge of coolant and proper quanity of oil. situations like this are kinda chasing the cause and as you eliminate things you find the solution.

[Jareds 89 LX-i]

It could be as simple of thing as a relay, either compressor or fans. When my a/c started blowing warm everytime I came to a stop, I figured out the fans weren't running all the time. Wiggle the relay a little and they come on. Replaced the relay, but later on it started doing the same thing. Turned out to be the plug in the fuse box wasn't making a good connection to the relay prongs. Bent the little spring thingy out a little so it fit tighter and it worked like a charm. Just a thought....

[3G Jester]

GAH. i loosened the pivot bolt and the adjustment bolt....BUT MY GODDAMND COMPRESSOR IS NOT MOVING.

i cant get the belt off

[SiR]

Originally posted by 3g Jester
GAH. i loosened the pivot bolt and the adjustment bolt....BUT MY GODDAMND COMPRESSOR IS NOT MOVING.

i cant get the belt off

Wip out that crow-bar! (dont bash it, just get some leverage)

[AccordChemist]

you all are all wrong. you are low on r12. goto honda and get it recharged.

mike

[ELM'sLX+CHL'sDX]

Originally posted by mike89lxi
you all are all wrong. you are low on r12. goto honda and get it recharged.

mike

Mike,

What makes you say that? I just had the r12 recharged last summer and when the compressor does start-up, the air is very cold. Just curious if you know something I don't?

Erika