My air conditioner works off and on. When it works, it blows cold. It shuts off randomly and without warning. I usually hear a clicking sound near the passenger side of the dash board when it goes dead. A mechanic told me that this was a rather common issue. Does anyone have any idea what the problem might be? Thanks a lot.

Evaporator freezing up? As a start, have the refrigerant charge level checked. Also, make sure there are no obstructions to the air flow.

My air conditioner works off and on. When it works, it blows cold. It shuts off randomly and without warning. I usually hear a clicking sound near the passenger side of the dash board when it goes dead. A mechanic told me that this was a rather common issue. Does anyone have any idea what the problem might be? Thanks a lot.

 

Sounds like the evaporator thermoswitch. This is supposed to shut the system off when/if the evaporator reaches 32F (the condensation would freeze). They fail quite often in an intermittent fashion. Remove the glove box. TS has 3 wires going into it and a probe on the back end that is stuck into the fins of the evaporator. wire colors on my diagram are re/black, brown/white, and green/red. Uh Oh, now I've forgotten which wires I crossed to bypass it (not that what I've done is a safe method).

 

I think I crossed the green/red to the brown/white to bypass it. The clicking you hear is from a relay. **edit: yes, those are the wires I crossed to bypass the TS. As OB99W suggests, it could be working correctly by sensing a freezing condition in the evap.**

 

Nick

I don't have a schematic; what happens if the red/black wire and the green/red wire are crossed? I crossed the wires as described below and the AC works but the fan blows at high speed and it won't shut off unless the ignition is off.

Wrong device, wrong wires. Was the plug white in color? 4 wires? If yes, you swapped the fan power wires that come off of the fan resistor which gives you 1, 2, and 3 fan speeds. Look up and slightly right (maybe left, it's been awhile since I've been in one) you'll see a slender black device hanging off the box with a two or three wire black plug on one end, the other end has a wire that comes out and goes into the box through a hole at the seam of the top and bottom peices of said box. That black thing with the wire attached is the thermister or thermosensor whichever you want to call it.

 

It can be replaced in the car w/o taking the box out....

 

Just remove as many screws as you can holding the top and bottom of the box together.

 

Then, with some good, long, needle-nose pliers you can remove "probe" from fins of evaporator.

 

Install new "probe" into the evaporator.

 

You will, however, need to remove glove box, ect. to make easy access and working space....

 

 

Hint: if the probe is not in all the way, or in at all, say 1/4-1/2" away from evap, the A/C might blow colder if the rest of the system is tip-top. Just keep in mind that it could freeze up by doing that.:cool:

 

Lewis

Going by the start date on this thread I would give it a rest.

Going by the start date on this thread I would give it a rest.

 

I replied to an old thread to get some assistance. Hopefully the suggestion above will help.

I assumed that when I removed my glove box that the plug with three wires going to it positioned front and center was the device I was going to splice. Once I did, as you described, the fan speed was full blast and the ac controls were urresponsive to fan speed, even the "off" button. The only way I could turn it off was to turn off the car. Does anyone have a photo where the thermister switch is located? I'm not concerned with my car freezing up since I live in a dry climate (Colorado) where 35%-40% humidity is considered a muggy day.

 

I wasn't aware that the probe could be replaced, just bypassed.

 

I guess photos would be a big help, if they exist.

 

Thanks for any help available out there.

 

Just had 2 pounds of freon added, with no leaks.

 

Would be nice to actually use it. AC blows cold at night, really cold. All I get is clicking relay during the day.

my ac goes off and on randomly as well.. pics would be great if anyone has them

Wrong device, wrong wires. Was the plug white in color? 4 wires? If yes, you swapped the fan power wires that come off of the fan resistor which gives you 1, 2, and 3 fan speeds. Look up and slightly right (maybe left, it's been awhile since I've been in one) you'll see a slender black device hanging off the box with a two or three wire black plug on one end, the other end has a wire that comes out and goes into the box through a hole at the seam of the top and bottom peices of said box. That black thing with the wire attached is the thermister or thermosensor whichever you want to call it.

 

It can be replaced in the car w/o taking the box out....

 

Just remove as many screws as you can holding the top and bottom of the box together.

 

Then, with some good, long, needle-nose pliers you can remove "probe" from fins of evaporator.

 

Install new "probe" into the evaporator.

 

You will, however, need to remove glove box, ect. to make easy access and working space....

 

 

Hint: if the probe is not in all the way, or in at all, say 1/4-1/2" away from evap, the A/C might blow colder if the rest of the system is tip-top. Just keep in mind that it could freeze up by doing that.:cool:

 

Lewis

 

Resurected post.

 

Mine is a 1993 Legacy wagon AWD, 5 speed

 

Well, I jumpered the green/red wire to the brown/white wire and the constant clicking and the ac cutting in and out finally stopped! FYI the part number is Zexel 582550-5600 1.5 degree C. I drove the car like this for over an hour in 83 degree temps in Boise (low Humidity) with no problems. It was glorious!

 

My questions...

 

Can I just keep the darn thing jumpered without incuring any damage to the system?

 

If I have to replace the thermistor/thermosensor/thermoswitch, can I cut the wires leading from it to the probe, splice in some connectors and mate it to a new thermister? It would seem to be a BIG PITA to split the evap box to get to the probe!

 

Any thoughts greatly appreciated!

[...] I drove the car like this for over an hour in 83 degree temps in Boise (low Humidity) with no problems. It was glorious![...]

 

Any thoughts greatly appreciated!

Thought: See my post #2 in this thread. If the humidity is low enough, the evaporator might not ice up even if it's too cold, so working for an hour doesn't necessarily prove anything.