E30 Heater Control - sliders bad

[thoraxe]

The E30 heater control (part 64111385972 ) is responsible for both vent selection as well as for enabling the AC to function. If the slider mechanism is not working right (electrically), the AC system will not engage, regardless of the switch position.

http://e30zone.net/e30zonewiki/index.php/Heating

"On 1987 and earlier cars with air conditioning (A/C) , the lever that regulates air flow for the instrument-panel vents also electrically controls the A/C compressor. To prevent condenser freeze-up and A?C system damage, the compressor is switched off if the lever is set below a certain point."

My car is an early '87. My repair shop (which I am considering ditching for awful customer service, although they do decent repair work) is telling me that my heater control sliders are going bad / shorting / whatever.

The part is discontinued and not available new. I could buy a recycled/salvaged one, but there's not a guarantee that it wouldn't either already have the problem or succumb to the problem.

I see a few of options here, although one of them I haven't been able to find information on:

1) rebuild/repair/remanufacture the sliders to fix the electrical issue
I've searched around for info on "e30 heater control repair" and whatnot, but did not find a lot of info. I'm sure there are some experts around who might know something. I could buy a used/recycled unit and sit it on the bench and play with it / disassemble it / clean it / etc. But without good info, there's no guarantee.

2) permanently enable the air conditioning such that it will come on regardless of the slider position
I am totally fine with this option, and comfortable with electronics. If someone could tell me what to short/jumper/wire/whatever, I think I can be OK with making sure the levers are not closed when trying to run the AC.

3) Forego air conditioning
Not an option, really.

4) Something else
Is there another option that I don't know about? From 09/87 apparently they used a different heater control: 64111385970
Is that part interchangeable? If not, is there a lot of work (other parts) required to update an early '87 to late '87 HVAC controls?

[Das Delfin]

#2 for the win

[thoraxe]

#2 for the win

Thanks for the support -- but how? :)

[jeffnhiscars]

That's not exactly how that works. The slider is a secondary switch which, as stated, is to insure your vents are open with the AC on. The way it works is there is a pcb behind the slider and a sweep that closes the AC circuit when the slider is about 2/3 to the right. Theres a connector to the pcb that you can remove and jump to bypass the slider microswitch. You should be able to get to it by removing the radio.

This will not turn on your AC but it will allow you to turn it on with the snowflake (as usual) regardless of the slider position. Its similar to the absence of a clutch pedal starter lock out. If you don't remember to step on the pedal you could damage something when you turn the key. Same rule if you bypass the slider switch....make sure its to the right when you hit the snowflake.

FYI Im in the middle of doing just this on our Time Capsule (early 87 eta). The sweeps got damaged when we swapped the dash and its not worth trying to repair it IMHO

[thoraxe]

That's not exactly how that works. The slider is a secondary switch which, as stated, is to insure your vents are open with the AC on. The way it works is there is a pcb behind the slider and a sweep that closes the AC circuit when the slider is about 2/3 to the right. Theres a connector to the pcb that you can remove and jump to bypass the slider microswitch. You should be able to get to it by removing the radio.

This will not turn on your AC but it will allow you to turn it on with the snowflake (as usual) regardless of the slider position. Its similar to the absence of a clutch pedal starter lock out. If you don't remember to step on the pedal you could damage something when you turn the key. Same rule if you bypass the slider....make sure its to the right when you hit the snowflake.

FYI Im in the middle of doing just this on our Time Capsule. The sweeps got damaged when we swapped the dash and its not worth trying to repair it IMHO

This is perfect. Yes, my AC control switch, as far as I understand, works fine. Although, in some cases, the snowflake is unlit but the AC Is definitely working (compressor engaged, blowing cold, etc).

I'm unfamiliar with your Time Capsule project - care to share a link? If you document the process of bypassing the slider microswitch I'd love to follow along.

[jeffnhiscars]

The link is in my signature :)

I'm working through the radio opening so pics may not be useful. The plan is to remove the connector to th pcb (it should just pop off) and to jump it with a small strip of sheet metal that's close to the same thickness as the board.then just protect it from shorting anything and it's done. You could also cut the wire and join the ends or,join a pair of butt clips but I prefe to avoid that if possible.

[jeffnhiscars]

You can actually replace the bulb in the snowflake although if it's intermittent that doesn't seem like the bulb. Easy enough to test.

[yosh]

Got this lying around if you want it. It was from my 87 vert. Shoot me an offer of you do.

[yosh]

Seems like all you need to make sure is that the two brushes on the slider makes contact with this section of conductor. Maybe it's as simple as modifying how the brushes are bent so they run over a different part of the condutor plating

[e30davie]

The previous owner of my car ran a wire directly from the AC switch to the air conditioning compressor clutch via a relay. so i can turn the AC on whenever i want regardless of slider position.

Prior to seeing this thread i didn't know why it was done (AC worked, so i didn't touch it......)

But it makes sense now why he would do that.

[jeffnhiscars]

the problem with adjuster the brushes is that they aren't brushes but just thin stamped metal arms. Once they get bent its near impossible to get them right again.

[jetavdk]

Getting to the party late after searching so is the consensus that the 970 will work in place of the 972? From the above posts I gather that a jumper wire needs to be inserted in the earlier cars for the AC to work. What if you always have the center flap open when running the AC; do you still have to run a jumper?

Finally, since the temp switch is the same for both the early and late cars it is my assumption that difference with the center flap slider will have nothing to do with operation of the heater, correct?

Cheers!

[jeffnhiscars]

The center flap is a "safety" secondary switch exclusively for the compressor. I don't know what a 970 or 972 is but if you push the snowflake then move the middle slider back and forth you should hear the compressor engage and disengage.mid not then your slider may be defective and a jumper would resolve that. There are other reason why a co press or would not engage so don't assume this is the problem.