Clicking under glove compartment when ac is on

[1990 Legacy L Owner]

Anybody ever have this problem. It happens when I have ac and max ac on and doesn't do it any other time. HELP!

TIA

[thehookeup]

yea i have the same problem in both my legs. but not when the ac is going. i think that its just actuator doors that are closing properly

[1990 Legacy L Owner]

Nah, this doesn't sound normal. sometimes it'll click 25 times in a row really fast. anyone else have this problem or a fix for it?

[Legacy777]

It's probably the a/c cut relay....which could be caused by something not right in the AC system. You may have moisture in the system, and it's freezing up the expansion valve.......

[1990 Legacy L Owner]

How can I check for moisture in the system?

[gto7419]

I get this clicking too - it happens anytime I use the hvac system - heat/vent/ac....

[Legacy777]

You can't.....you have to evacuate the system, preferably change the receiver drier, pull a vacuum on the system, and then recharge.

However I'd have someone look over it, or at least try and pin point where the clicking is coming from. It's easy to remove the glove box.

[def09]

With the A/C on the relay clicks on and off when the engine is under load, heavy throttle. Trips the A/C compressor off to reduce A/C compressor drag. The full defrost setting runs the A/C also. Anyone with a dead A/C hear any clicking?

[Legacy777]

The ac is cut off at full throttle only.

The ac will also cut off if your refrigerent is under or overcharged.

[91riored]

ok well my 91 ss a/c is shot no cold r-12 freon is $$$ so i havn't recharged.. the def. button will somtime work sometimes not all other setting are ok. the fan only works on 4 (resistor) or is this problem bigger then i think? it makes sense that the def won't work cuz the a/c is shot so comp shuts down. but is this why blower is bad? where is the blower resistor? in control? should control be changed

[Legacy777]

The blower resistor is behind the glove box, and shouldn't be related to the ac not working.

[scuzzy]

the blower resister is behind the glove box but installed IN the air box.

the magical device of choice here is the thermostatic switch, I believe it has two or three wires going to it and looks like a little plastic connection with one or two white wires that go around/up the airbox into the top.

I haven't been able to get at it yet, but supposedly the white wires are installed into the fins of the evap inside the air box, when the thermostatic switch gets too cold it cuts the A/C compressor off.

this switch fails, mine has - it gets stuck open, stuck closed, or clicks on and off rapidly at temperature switch points.

they're expensive to replace if you get them new, somewhere around $150; my "hack" for the last two years has been to ground one lead out of the ECU side of the switch (I can't remember which, don't ask me; I did some measuring with a multimeter when the switch was working) and run that to a switch that controls when the lead is grounded, ground the lead and the ECU cuts the compressor clutch on.

[ttmuench]

I have the same problem with my thermostatic switch. I've found that grounding the "L" terminal on the thermostatic switch cycles the compressor back on.

Here's another post where I've commented in more detail on this issue.

http://bbs.legacycentral.org/viewtopic. ... tic+switch