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Heater/ AC Issues

1K views 4 replies 2 participants last post by  dodgethis9271 
#1 ·
I've got a fairly crazy heater in my 1987 300D (it's a US one, so US push button climate control system)

For years it has always squeaked. It makes a high pitched chirping noise a lot. But lately it's gotten worse. Now it turns into an occasionally gridining noise, it sounds like something it hitting and getting stuck and fighting to get free in the dashboard.

Also my center dashboard vents only work part of the time. And I see only to have the noises when the center vent isn't working. My two window vents work fine, as does the one along the windshield I think.

Next problem: My off switch doens't work. The heat or AC is constantly on. If I have it set to off with the fan on the low speed setting air still comes out. If I push the auto or full speed setting the fan just blows higher, the same as if I have it on any other setting.

Then there's the defroster: It works fine, especially when I set it to high. It's after I'm done using it that I have a problem. If I switch the system to off or all vents the fan will cut out and then every few seconds it will turn onto full blast on the defroster for a few seconds and then cut out again.

We've had this thing looked at and worked on many times over the years and nothing has helped. Does anyone know what could be causing any of this?
 
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#2 ·
Climate Control!

Here we go, first off the center vents are only for cold air, so thats why they only sometimes work.

The chirping noise is one of two things either the fan or the air sampler which has a hose that goes up by the sunroof/rear view mirror or if it gets faster or slower with actual fan speed the motor needs replaced or there is too much debris around in with it.

If fixing those things doesn't cure your ill's then go big bucks with a new push button CCU (which I have a spare if you need one they go for about 300 new)

I bought mine because I did all this in reverse order :crybaby2:

Hope that helps.
 
#3 ·
Thanks for all the advice. I didn't know that about the center vents, but that explains a lot about not getting heat through them :D

Yeah well I was hoping it would be something cheap. I'm taking the car to the dealer soon and I suspect that they might be able to fix these little things for not too much.
 
#4 ·
#5 ·
Right then forget the dealer...

I was going to have th airbag servied so while the dash was off I figuerd I'd have them take a look at the clime control but I'll skip that then.

Do you know how much an exterior temperature guage readout costs to replace? Mine is completely dead. It sill lights up at night with the lights on, but it doesn't have a display any more. I think all the liquid crystals melted throught ehir holder or something because they've blacked out part of it.
 
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