[Peter]

Just my guess: I agree with Kwikt, you may want to make sure that the fan is clean. As you mentioned, you car does not have a cabin air filter and the fan could suck in some foreign objects, like maple seeds or leaves. The Recirc mode changes the vents position, thus leaving more space between the fan and the vents, the foreign objects are not not rubbing anymore, so the sound stops.

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[Sears]

I'll double check that it is clean (the fan that sucks in air through the vent in the dash). Thanks for the tip.

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[flash]

i sure wish i could nail down what is wrong with the car in the test car. it has a good charge and a new compressor. aiming the laser thermometer at the center vent, i can find a spot that is cold, but most of it is room temp. it also goes wonky and drags on the engine if i go above 2, as if the compressor were dragging

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[vliegwielolaf1234]

[quote name='flash' timestamp='1348868452' post='133146']

i sure wish i could nail down what is wrong with the car in the test car. it has a good charge and a new compressor. aiming the laser thermometer at the center vent, i can find a spot that is cold, but most of it is room temp. it also goes wonky and drags on the engine if i go above 2, as if the compressor were dragging

[/quote]

Is it new or rebuilt ?

Sounds like a bad compressor to me .

Other thing could be a blocked expansion valve , but then the compressor should shut off when the pressure get's to high , put a gauge on the high side to see if the compressor is building up pressure , and see if it does it shut's off because of high pressure switch getting activated .

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[BeBe]

I was having a problem where I was getting heat with the temperature control turned all the way down. One time when I was driving with the top up and the radio off, I realized that there was a click coming from the passenger footwell area. One click; heat for a minute or two. Next click; ambient for a short time. Cycle repeats. When I had it in the shop, I had them investigate. I originally thought it might be a relay. They replaced a heater support clip (94457231400) and a door clip (94457221700). Problem solved.

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[lbpesq]

Sears:



Did you ever figure out the cause of the clicking that stops when you engage the AC? Now mine's doing it, too.



Bill

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[tamathumper]

I have not, but as I believe mine is related to those vacuum-controlled solenoids in the passenger footwell, I'm curious to see what happens when I put everything back together with (hopefully) improved vacuum.

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[tamathumper]

I'm curious to know if you got this resolved Sears. My vacuum issue is resolved (if I ever really had one), but the clicking continues and I have new data points.



The A/C worked fine all summer, and there was no clicking. As fall hit and temps got cooler, I might get a click or two backing out of the garage in the morning. Now, as the real cold weather is here (35 this morning, 29 tonight), the clicking is back with authority. Also with the shortened days, I had the opportunity to need the headlights this morning and tonight, and noted a lot of missing lights.



1. It happens only when the interior of the car is very cold. It does not happen when everything warms up.

2. It clicks a lot when I hit a bump in the road.

3. When clicking (or stuck in "click" mode), the lights on most of the climate control go out. Only the light on the fan control knob remains lit.

4. Pressing a climate control-related button, or sliding the up/down sliders, will momentarily engage whatever is wrong, it will click, and the lights will flicker.

5. When clicking (or stuck in "click" mode with the lights out) the heat does not work. I assume the A/C does not either, but it was too cold to tell.

6. I noted on the left side of my climate control, the clip holding the fascia plate is probably broken, as it sticks out just a tad and I could push it in past flush.



Are we thinking malfunctioning climate control unit here?

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[Paul W]

tamathumper: from your description, it sounds like the system HVAC dampers are vacuum controlled and not electric motor controlled? Either way, there has to be either an electric motor that controls the air flap dampers, or a solenoid that controls the vacuum to the tube that controls the damper.



If you are getting clicking and there are electric motors for the dampers, they are "out of range" and reporting this back to the control unit. They would have a resistor associated with the position of the damper.



If they are vacuum tubes, the dampers still might have a resistor and report back to the HVAC head unit. This could either have a leaking vacuum hose/connection and causing the damper not to position correctly so the head unit is cycling the solenoid or it might be somehow knowing that the vacuum isn't holding and is cycling it....



I guess it's time to look at the wiring diagram for the HVAC system. I'm on the road traveling....will see if I can look at it....but it shouldn't be hard to figure out.

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[Paul W]

After a quick look at the CC wiring diagram, there are two solenoids associated with the system, the heater and the recirc function. There are three motor driven HVAC vents with position indicating resistors, the defrost flap, footwell flap and mixing flap. It could be either the heater solenoid that you are hearing or one of the flaps cycling due to being "out of calibrated range" for the resistance reading. Considering you don't get heat, I would say either the heater solenoid or footwell flap.



What happens if you depress the front window defroster button when this happens?



Do you know where the heater solenoid is? Can you listen to it when this is going on with a stethoscope or a long screwdriver to see if it is cycling?



It could be either the HVAC head unit or the component. Considering the lights on the head unit (which I could not find on the wiring diagram easily) are going out, I would suspect the head unit. It is very easy to pull, and you could always do a resistance/12 VDC operational check on the heater solenoid from the wiring harness once the head unit is disconnected.



pw

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[tamathumper]

Thanks for your response. The flaps are controlled by vacuum solenoids AFAIK, and I believe those are what is rapidly clicking. It's definitely a rapid "relay" clicking sound coming from the center wall of the passenger footwell and not up inside the dash. Speed-wise it sounds like fifteen or more clicks per second at its fastest.



If I depress the front window defroster button, or move any control on the climate control unit while the unit is in "stuck off" mode, the lights may flicker on, then go right back out. Once the car warms up, everything comes on and works correctly.



I don't know where the heater solenoid is, if it's different from the heater control valve, which I replaced a few hundred miles ago as a preventative measure.



I would not expect the vacuum solenoids to be able to make most of the lights go out in the climate control unit on the dash, hence my suspicion I have something amiss in there.

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[Paul W]

Here is the HVAC wiring diagram....you can see what I am talking about...I don't see the flap solenoids in the wiring diagram. I would have to look at the components to figure it out. I can't find anything on the HVAC system in the repair manual, only a few pages on the AC system.

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[tamathumper]

Thanks, Paul W. I do have those pages printed out, and am going over them. I'm assuming that those two items marked "Solenoid Valve Heater" and "Circulating Air" are the vacuum solenoids in the passenger footwell.

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[flash]

vacuum leak - lol



seriously though, is it a "clicking" or a "popping"? does it only happen once, or does it repeat? if it repeats, is it rhythmic? did i miss that somewhere?

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[Paul W]

I guess you would have to read his post to figure that out - lol



Flash, I think you need to make fun of others instead of me. Unless you want me to start nit picking everything you write.

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[flash]

i went back, and did in fact see the pace comment. i asked if i missed something. looks like i did.



ok - that sounds like a relay, as he suspects. depending on the year, there are some relays behind the ECU.

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[tamathumper]

The funky party is most of the climate-control lights going out - I'll dig in there this weekend and see if I can locate any loose connectors, burned traces, or what-not. I didn't want to mess with it, but it looks like the clear fascia and other parts are now available for only a few hundred bucks - not $900 like a few years ago for a whole new unit.

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[Paul W]

I was thinking about this, and I agree that it could be a bad head unit, or just as likely, a bad ground that somehow takes care of itself. It could be a bad ground for the HVAC unit, or it could be another component on the same grounding circuit that has a bad ground and is back feeding through the unit, and once the car warms up it clears and all is good.



And your description of the issue sure sounds like a bad electrical connection. I would take it out (easy to do), inspect the wiring as you suggest, and then make sure you find the grounds and remove the wire and clean the post.



If the car was cold, you could check for 12 VDC and ground resistance with a multi-meter, but I doubt you are going to find anything as it sounds like it is an issue when a current is trying to pass through, which a multi-meter will not provide that type of load.



Good luck!

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[tamathumper]

Thanks for your thoughts, Paul W. Much appreciated.

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[kwikt]

I'm saying it's the unit. I have one on the shelf that does the same thing...... only sometimes. If you were closer I'd let you try the one in my car and the "clicker". Only takes a few minutes to remove.

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