Air Conditioning

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VPRRAM
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Air Conditioning

Post by VPRRAM »

Newbee here,

I just picked up a 1979 633csi, it has factory Air conditioning, and the fan works till you turn the knob to "cold" then the fan turns off...Yes I've had it recharged, but no luck. The air con pump never turns on, been searching the internet, can't seem to find any ideas...
Any help to get me going in the right direction, would be much appreciated.

Fuse 14 is good.
Replaced the relay next to fuse 14 (found those ideas on the web)

Thanks so much,

Mike AKA VPRRAM
bpoliakoff
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Re: Air Conditioning

Post by bpoliakoff »

Could be a bad switch But there is also a micro switch on the back of the HVAC panel found only on the early cars. I am not sure of it's function but definitely has to do with the A/C It is actuated by the fan speed switch on the right of the panel in the rear. Not many people are aware of this but mine was found to be broken when I disassembled my car. They are available from BMW for around $70 but I found mine in an electronics supply store for less than $4 64111360634
81 Euro 635 M90 with motronic. Currently under a complete nut and bolt restoration. Pictures at
flickr.com/photos/bertsphotos.
VPRRAM
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Re: Air Conditioning

Post by VPRRAM »

thanks, i will look into that switch,

Mike
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Re: Air Conditioning

Post by bpoliakoff »

If needed, I have plenty of early HVAC panels with switches in them, intact
81 Euro 635 M90 with motronic. Currently under a complete nut and bolt restoration. Pictures at
flickr.com/photos/bertsphotos.
BenM635i
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Re: Air Conditioning

Post by BenM635i »

Does your standard blower work for hot and cool air? Do you get variable speed when when using the fan speed switch and also then it jumps to maximum with a slight click when you turn the dial fully right?

Assuming so then everything must be working up to at least the AC selector switch.
Heater Air Con Blower Control.PNG
Heater Air Con Blower Control.PNG (159.52 KiB) Viewed 4595 times


I would test the AC selector switch.. if that works ok then its either the transistor in the AC blower housing or the blower select relay would be my guess.
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635sharknose
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Re: Air Conditioning

Post by 635sharknose »

Ben, isn't this a wiring diagram for a later model (E28 based)?
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VPRRAM
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Re: Air Conditioning

Post by VPRRAM »

BenM635i,

Yes the fan does work and is variable, it quits blowing when you turn it to the "cold side", so I'm thinking the AC selector switch...more fun for me...

Thanks all, I will keep you posted.

Mike
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Re: Air Conditioning

Post by GRNSHRK »

Ben, same question as 635sharknose posted, as I think that wiring diagram is for later model series 2 version :-k

Plus one on the micro switch that's on the back of the HVAC panel =D>

What it does is complete the ground connection for either the heater or A/C blower, crazy, I know :-?

I'll see if I can find the wiring diagram for series 1 and post it [-o<
:mrgreen:
Bobbo
1980 633 CSi Cypress Green/Pearl Beige
2017 X5 M Sport Xdrive 35i Carbon Black/Ivory White
2005 330 Ci ZHP Cabrio Imola Red/Bone/Black
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Re: Air Conditioning

Post by bpoliakoff »

I have the pre 82 ETM for American cars if diagram needed i can phone picture it and forward. I also may have tthe Euro but have to see if I can find it.
81 Euro 635 M90 with motronic. Currently under a complete nut and bolt restoration. Pictures at
flickr.com/photos/bertsphotos.
BenM635i
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Re: Air Conditioning

Post by BenM635i »

Bobbo and Paul, do believe that my eagerness to post after visiting the forum for the first time in months may have led me to not read the original post properly :D completely missed the fact that this was an early car :oops:

Looks like you have sussed the likely culprit .. the little known switch next to fan speed dial.
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635sharknose
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Re: Air Conditioning

Post by 635sharknose »

BenM635i wrote: Sat Jul 03, 2021 7:26 am Bobbo and Paul, do believe that my eagerness to post after visiting the forum for the first time in months may have led me to not read the original post properly :D completely missed the fact that this was an early car :oops:
Welcome back Ben, please stay on board, we like to have you here :D.
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BenM635i
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Re: Air Conditioning

Post by BenM635i »

Cheers Paul.. glad to be back on what is quite simply the best forum on the interweb :D

Now if we can get Mike’s air con working properly it will be a success.
'85 M635 #160
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Re: Air Conditioning

Post by GRNSHRK »

OK, copied the HVAC Schematic out of my electrical manual, the micro switch is called the "HEAT-COOL SWITCH" which you can see completes the ground circuit to either heater or A/C blower, weird way to wire it, I know :-?

But if that switch craps out going either direction, that corresponding blower will not function at all [-X

Placing my bet on that being your problem [-o<
Attachments
HVAC schematic 001.jpg
HVAC schematic 001.jpg (325.69 KiB) Viewed 4342 times
:mrgreen:
Bobbo
1980 633 CSi Cypress Green/Pearl Beige
2017 X5 M Sport Xdrive 35i Carbon Black/Ivory White
2005 330 Ci ZHP Cabrio Imola Red/Bone/Black
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Lbs6
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Re: Air Conditioning

Post by Lbs6 »

I just went through this process over the weekend. Last year my Polaris car had identical symptoms, which I convinced myself that the diode had failed. Seeing this post last week I decided to prove my theory. Unfortunately the diode checked out fine, so Bert and Bobo were right on. That micro switch on the temperature selector was bad in one position. Heater fan would work fine but when you rotated into the ac position the fan shut off. Unfortunately the switch is riveted in, so you need to drill out those for replacement. I had another control panel, so I was able to diagnose the switch easily and swapped out the whole panel. Changing out these panels requires lot of patience, be very careful with the capillary tube for the ac controller lots of small hardware also to deal with. Luckily for me my son Luke help make it happen without to much grief. Let us know how it turns out for you.
Leonard
80 633 polaris
79 635 (euro) fjord
85 635 schwarz
VPRRAM
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Re: Air Conditioning

Post by VPRRAM »

Looks like I will be taking out the heater control panel. You guys are a lot of help and I really appreciate all the help....

But...I had to move to rebuilding the front brakes. When I bought the car the calipers were really rusted (the only rust I can find on the car!!!)
So I decided to remove, rebuild and paint..Bought the rebuild kits, for the front, and am in that process of de-rusting and rebuilding, should be done this week or next.

But im thinking that with all the comments, its that micro switch.

Again Thanx for all the help. I will keep you all informed...

Mike
Dmckim
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Re: Air Conditioning

Post by Dmckim »

Resurecting this thread as I have a early car AC issue. I replaced the heat/cool switch as Bert described a number of years ago. My issue is that the compressor only engages sporadically when turning the tempature switch. Blower motors switch fine from heat to cool, so I dont think it is the switch again nor the #1 relay. I have some potential thoughts:

Capillary tube isnt seated correctly
Tempature switch itself is kaput
The #2 Relay is bad; it is not the one behind the panel, it is furhter down the line somewhere (not sure of location).

Any other thoughts? The temp switch is unobtanium, although I do have some spares in unkown condition.

Dale
1980 633csi
1980 633CSi
1987 325is (sold)
2001 740iL Sport (sold)
2007 328xiT (Sold)
2014 320dT (Sold)
Current: 2023 Jetta GLI M/T
2007 GMC Sierra,
1972 Pontiac LeMans Sport Convertible
bpoliakoff
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Re: Air Conditioning

Post by bpoliakoff »

Dale I forget, what year is your car?? I have the electrical manual manual for pre 82 NA cars. I can probably copy the a/c schematic if it doesn't take a zillion pages. I am off to Europe for three weeks Friday. Let me know and I will check it out Oh, what about the cut off switch on the receiver drier?
81 Euro 635 M90 with motronic. Currently under a complete nut and bolt restoration. Pictures at
flickr.com/photos/bertsphotos.
Dmckim
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Re: Air Conditioning

Post by Dmckim »

Mine is an 80. I have the ETM - appreciate the thought. From reading it and playing with the car, I think it is the temp switch or relay but know I am not the smartest guy in this room!

Dale
1980 633csi
1980 633CSi
1987 325is (sold)
2001 740iL Sport (sold)
2007 328xiT (Sold)
2014 320dT (Sold)
Current: 2023 Jetta GLI M/T
2007 GMC Sierra,
1972 Pontiac LeMans Sport Convertible
Dmckim
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Re: Air Conditioning

Post by Dmckim »

Not sure what the ultimate culprit was, but I replaced both relays (both are behind the panel; my earlier post was incorrect) and the temperature switch from a spare panel. Appear to be working as of now!

Dale
1980 633CSi
1987 325is (sold)
2001 740iL Sport (sold)
2007 328xiT (Sold)
2014 320dT (Sold)
Current: 2023 Jetta GLI M/T
2007 GMC Sierra,
1972 Pontiac LeMans Sport Convertible
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ColinC.sg
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Re: Air Conditioning

Post by ColinC.sg »

Hi Dale,
I have been experiencing this problem too.
The heater blower works most times, but when turning it to cold air, the blower doesn’t function all the time, it needs a bit of switching it back and forth and fiddling for the cool air blower to start…

Mine is a 1981 RHD car
Here is a pic of the air con control unit
Image
did you replace the relays and the switch?
Would you have pictures and do you know which would be the wiring diagram that represented your car?

Appreciate you help on this.
I haven’t yet tried to open this up, but will have to get around doing this ultimately.

Thanks in advance!

Colin
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691B708D-F7A6-432F-AD9F-3D6F29D2ECB1.jpeg
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Dmckim
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Re: Air Conditioning

Post by Dmckim »

The problem you describe was the original issue I had a number of years ago. It's the microswitch for the sounds of it.

As had been said here, it is a generic switch. Actually used on microwawe ovens back in the day. Part number I have is XGG2-88-Z1.

As also mentioned, one issue is that I think it is riveted in to the control panel. I tried to rivet it myself, and ended up cracking the switch! Just find some small bolts and nuts to fasten it. I cannot remember how I removed the original one.

Hope this helps.

Dale
1980 633CSi
1987 325is (sold)
2001 740iL Sport (sold)
2007 328xiT (Sold)
2014 320dT (Sold)
Current: 2023 Jetta GLI M/T
2007 GMC Sierra,
1972 Pontiac LeMans Sport Convertible
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ColinC.sg
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Re: Air Conditioning

Post by ColinC.sg »

Dale,
Noted. Thanks for your reply.
Will work on replacing the switch.
Appreciate your assistance.

Regards
bpoliakoff
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Re: Air Conditioning

Post by bpoliakoff »

Bought mine in electrical supply store that sells computer repair parts
81 Euro 635 M90 with motronic. Currently under a complete nut and bolt restoration. Pictures at
flickr.com/photos/bertsphotos.
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ColinC.sg
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Re: Air Conditioning

Post by ColinC.sg »

Dale,
Finally go to the electronic store and got the micro switches… there was a generic one for about S$2.50 but for the exact item i had to find a shop which would order it for me at $5 (bottom one in the pic)
D6484A12-95A4-461B-8AC1-90E51550E0E3.jpeg
D6484A12-95A4-461B-8AC1-90E51550E0E3.jpeg (785.54 KiB) Viewed 1020 times
Now i have to try to figure out how to remove the panel to get to the switches.
Thanks for the help so far!


Do you have any link to some guide/instructions?

Thanks
Dmckim
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Re: Air Conditioning

Post by Dmckim »

I have tried to document this so many times, but never end up doing it. I think it is much easier to remove radio as well for access to the panel, so I included this as well.

Pop out and unplug cigar lighter and hazard switch. Should see 4 large phillips head screws. Remove. Depending on your radio installation, should all come out as one unit with the metal mounting unit.

HVAC Panel Removal:

- Turn controls all the way in one direction. Doesn't matter which. This will help align them for reinstallation.

- Remove plastic covering to the left of the control panel. There are two phillips head screws. I think maybe the only one has to come out, but I seem to forget this and always take out 2. Small magnet will help grab them and prevent them from falling into the abyss.

- Remove vent lifter knobs. Should pull right off easy

- 1 small phillips head at the top of each vent lifter. They are black and hidden. Need to come out. Again, magnet will help.

- Reach underneath where radio was and push out panel from back. Wont come out all the way.

- At this point, you should have enough clearance to unplug rear defroster.

- Unhook white control arms from back of panel. They "plug" in; there is a small plastic bump that you need to press in.

- Unplug the control panel. I think there are two main plugs on the back.

- From there, you are on to the replacement of the switch. Again, very delicate work.

Hope this helps.

Dale
1980 633CSi
1987 325is (sold)
2001 740iL Sport (sold)
2007 328xiT (Sold)
2014 320dT (Sold)
Current: 2023 Jetta GLI M/T
2007 GMC Sierra,
1972 Pontiac LeMans Sport Convertible
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