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Ken Gaydos
12-29-1998, 06:59 PM
Looking for anyone to help. The heater in my '82 E23 735i is kaput. First the blower quit and now there is no power to the control. Info on where to get wiring diagrams will help as well.

Callan Campbell
01-02-1999, 03:58 PM
First check the fuses at the fuse block. Old e-23s with the ceramic fuses can have voltage supply problems with corroded conns. or melting holders that slowly move away from the fuses. The blower could be seized but try the defrost button first to by-pass the transistor packs that control the lower speeds[every speed excp. high].If nothing is working you may have both a bad blower and a dead microswitch which is located in the middle of the thumbwheel contols. This is what makes that clicking sound when you turn the air volume thumbwheel. If you send an envelope with postage prepaid to the below adds. I can mail you the copies of the a/c-heater wiring diagrams and the training info that BMW printed when the system was new. I'll include r&r notes as well as prices on new&used parts in case you need more than one thing. I need to know 1/2 things first: Were all blower speeds working before the blower died? Did the little green lights above the vent button flash on/off when you tried to turn the system on. Sometimes the board will make a chattering sound as the bad microswitch tries to function. C/O: Perillo BMW 2825 N. Halsted Chicago IL 60657 Attn: C. Campbell

01-12-1999, 03:44 PM
<Thanks for the info. This car is equipped with factory air and climate control system. Also have the newer blade type fuses. I will send the envelope quickly to get those diagrams, that will be extremely helpful. The fan did work at all speeds as it should before it gave up the ghost. That clicking sound would happen as well, drove me nuts. There is what appears to be a vaccuum pump that controls the pneumatic heater controls mounted behind the power steering fluid resevoir. The pump worked, made a lot of noise, adn then quit one day. This is when the contol unit lost power. The electrical connection to this pump has both leads to ground. Luckily the vents stuck in the heat position, that way I get some heat while cruising.

01-16-1999, 04:09 PM
ok. I'll look for that envelope at work. Meanwhile, from the sound of things the blower has seized; and the vacuum pump died too. The pump has quit for 3 reasons: wiring/fuse problem, old age or much more common, you have a vacuum leak in the a/c-heater vacuum system. The way the pump works is this:Fuse#16 provides power to both the pump and the aux. fan circuit . Ground for the vacuum pump is constant by way of point 104 which is the body bolt in front of the fusebox{right next to it} Relay K5 is supposed to provide power to fuse#16. It's mounted in the fusebox at the far left side and also called an unloader relay. If this puppy is bad you should also lose alot of other things so I assume it's ok. Most pump failures happen from vacuum leaks so check for power&ground first then we'll head toward more complex waters. The vent functions of only heat and defrost air are correct for a 7-series in "fail safe mode" . The engineers at BMW designed the system so that if the vacuum supply fails the defrost vents are mechanically left in the open position and the heater valve gets the same treatment. This way ram air can force itself across a full, hot heater core then end up at the windshield to keep it clear. The next problem involves finding the leak[s] and fixing them. This can be tricky since not all lines and vacuum vent motors are turned on all time. Instead, depending on what you've selected , the control unit can turn on only what it needs to in order to maintain the desired temp. setting. The most common failures are as follows: feed hose[black] in the engine compt. breaks or falls off the intake manifold fitting. 2- heater valve gets hole in vacuum diaphram. 3- Defrost motor does the same thing only it has 2 diaphrams because it's a 2-stage motor. 4- Recir. motor goes bad. 5-either one of the front cowl motors[the flaps are visible under the large blk. intake grill at the back of the hood/windshield] or the #$%* hose falls off the plastic fitting that connects the cowl motors with the heater box. Think of this as a plastic junction assembly for vacuum hoses. Sometimes the rubber multi-fitting vacuum "manifolds" will split with age but you can usually hear a whistle inside the dash by the lower left center console section if this has happened. All the sceno. I've listed are repairable without! removing the dashboard. The following items will mean its r&r. Fresh air/face vents failure . Footwell vents{I think} or a cut hose that runs inside or at a non-reachable spot. Sigh, I know this sounds like a brick wall but 95% of the problems I fix on these cars doesn't require even touching the dashboard. just don't let inexper. hands get near the heater system and you'll be ok. To test & find leaks means that you're better off calling me at the # below because a certain amount of tools are called for to make this a easier job.. 1.773.525.9817 ask for callan m-f only 8am-5pm CST

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