Climate Control weirdness

[Elessee]

I have an '88 LCS.

The little yellow indicator lamp just above the "OFF/AUTO" button on the Electronic Climate Control has been blinking whenever I activate it.

At first it happened only rarely many months ago. Now it's almost always blinking whenever I want heat/cooling and press that ON button. It blinks steady at 2 times per second.

All the heat and cooling functions are normal.... fans.. heat.. cooling.. temperature selection. Everything works.
I haven't done any work on the car for a while.. haven't disturbed anything.

If someone knows why that LED lamp blinks I'd appreciate the input.

 

[ridindirrty]

Fault

It means there's a fault somewhere in the system. Do you only use the AUTO funtion? If so, next time you want heat or cooling, try using the manual functions. Press FLOOR or PANEL first. The selected funtion will light up along with the AUTO / OFF light. See what happens then. When you use the auto function the climate control decides where to direct the air and what fan speeds to use to reach and maintain the chosen temp. The issue with mine turned out to be the door or actuator that directs the air between the different output vents. If i leave it on FLOOR it's fine but as soon as i try to switch to PANEL, the lights start flashing becauuse the actuator can't complete the desired function. If it's jammed or failing electrically i don't know but this is the issue. Sometimes it works but more often not. Occasionally it will show a fault and start blasting the air out the defrost vents instead. Very annoying.
There is a self-diagnostic function you can do through the control unit. It's posted here somewhere if you do a search.

 

[jimmyblue]

Ours has done this intermittently ever since a third-
party stereo install. I am suspicious about perhaps a
messed up ground, or cobbled power wiring. But haven't
gotten around to it....

 

[Elessee]

It means there's a fault somewhere in the system. ..... try using the manual functions. ....... The issue with mine turned out to be the door or actuator that directs the air between the different output vents..... If it's jammed or failing electrically..

I just started it up cold a couple of times, and tried the manual functions and no blinking .. at least for a time. Then it started blinking after the engine idle smoothed out and when (I guess) the computer was finally ready to direct the air to where I commanded it.

I now recall something making noises early last winter, near the center of the dashboard.. I figured it was a vent-door making noises like it needed oil.. a pretty loud rubbing somewhere in the dash.
It happened in Reno when they experienced an unusually cold spell, like zero degrees F and below for a few nights.

Thanks for the tip. I have the manuals and will look for that diagnostic, and search here if it's not there.

btw, did you get into your dash to fix your vent? I have yet to take any of it apart, except for a radio R&R, and am not looking forward to taking it apart... wondering if it's worth the effort.

 

[ridindirrty]

btw, did you get into your dash to fix your vent? I have yet to take any of it apart, except for a radio R&R, and am not looking forward to taking it apart... wondering if it's worth the effort.

Nope, i never got around to it. I'm pretty sure it's an electrical thing rather than a mechanical issue because under certain conditions I can get it to work fine. Don't ask me why but this is the routine that works. I never actually turn the heater off anymore, just leave it on. If I shut the car off with the vents on FLOOR, it will always fire up, no flashing lights. MOST of the time if I go from the floor to the dash vents it will work but occasionally not...the door gets hung up. Put the setting back to FLOOR, shut the car off, restart and it blows out the floor vents again. The main worry for me is A) no heat at all or B) not being able to get the heat on the windshield to defrost which so far has not been a problem (knock on woodgrain ) I'm pretty sure that sound you're hearing is the MIX door (the one that lets in the outside air to control the temp), it makes that kind of rubbing sound as you adjust the temp, it moves a small increment per degree of adjustment. Sometimes I can hear mine going mental inside the dash all on it's own with no input from me. Leads me to believe it's a short or a bad connection somewhere. What i do to cure this is to cycle the temp buttons to full HOT and back to full COLD and then it settles down. Just like a staticky knob (potentiometer) on an old radio...if you fiddle with it a bit it sort of self cleans from the friction and re-establishes a good connection. Basically, these cars are old, dirty and corroded. Everything just needs a good cleaning.

 

[Elessee]

There was a new twist to this. Not only are the button-LEDs blinking but the temperature setting number also started blinking last week... so I figured I better do something.

After messing with this thing today, now I'm almost positive the "Temperature Blend Actuator" or some related part is the problem.

At first there was no heat. I could hear the blower running at full speed but nothing much came out of any vents. Then after setting temperature from 90F to 60F and back again, and hitting different control buttons, the blinking lights stopped and heat was blowing out full blast.

I went from 90F back down towards 60F to see if "It fixed itself!" but the lights started blinking again..

Cooling is never a problem. Heating is the problem.

Anyway, i think that blend door is sticking towards the COOLING side, and it's hinge or seal or something needs lubrication.

(It may be electrical.. but I cannot get into the diagnostics routine due to the blinking lights / fault for some reason.. To activate self-diagnostics hit OFF/AUTO and DEFROST simultaneously, and then hit AC within two seconds.)

oops..
[EDIT] I managed to run the diagnostic routine. Press OFF/Auto and Defrost buttons, and release them. Then press AC.

Faults are 01 and 02.
01 = Blend Door out of position
02 = Floor/Panel actuator out of position.
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From the manuals it looks like the heater core and AC evaporator are housed in a box near the center of the dash. The Blend Door is also in that box.

I tried to find an access point where I could get a hand on the blend actuator or the actuator door hinge ... can't see anything through the glove box.. nothing from the driver side.. Might see something if I remove the radio?
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Removing the dash is out of the question, imo. But there's gotta be some way to lubricate or jiggle that blend door's hinge? How about spraying some WD40 into something like the outside-air intake and lube the whole system?

no way am I removing the dash.. this old car might not survive it..

 

[Elessee]

[How about spraying some WD40 into something like the outside-air intake and lube the whole system?]

hehe...
Spraying something into the outside-air intake vents is a fast way to thoroughly perfume the interior of the car.. WD-40 isn't exactly my preferred fragrance, but I've smelled worse. Probably best to leave both doors wide open during this operation.

(The intake vents are under the hood at the base of the windshield, wherein the windshield wiper mechanism lies.)

I sprayed a few shots of WD40 into the system. Thus far it didn't free up any stuck vent door, nor has it made things worse by poisoning a temperature sensor or doing similar destruction.. it just stunk up the car..
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The only consistent error I see is the FLOOR vent fails to open.

No matter heat or cooling, regardless of which buttons are pressed, the floor vent is stuck closed. FLOOR air is directed to either the panel or defrost vents. So, at least I should have heat come Winter time, for which I'd be grateful.

In one of about hundred attempts, the floor vent did open, so I think both the electrical and mechanical stuff is functional.
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Now I gotta dive into the manual and pinpoint the FLOOR vent, it's circuit and actuator, etc. Ideally I'll be able to trace a loose connection.