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Discussion Starter · #1 ·
I have been working to get the a/c up and running in my GTV6 and found something puzzling during the process. Does anyone know the function of the microswitch on the heatervalve? I found that it controls the power to the auxiliary fan in the tropic-aire system. When the heater control is set to max cold the switch turns off that fan. When I move the slider slightly to the right in the hot direction, the switch sends juice to the other fan. Why would it be wired this way? Seems backwards. Why would you ever want the other fan turned off? Everything seems to be working according to the wiring diagrams but the design itself makes no sense.

Ideas?

Also, on a side note, I may have a fix for the worn out blower motors in these cars. I have attack plans. The plan I am implementing now is based on an idea I got from a mercedes forum. This guy replaced his worn out oilite bearings with ball bearings from roller blades. I currently have abec 7 bearings installed on the motor (with zip ties!! OMG!!) At first I was worried because they got quite hot when I was testing the design. But I read an article from SKF regarding temperatures and failure modes for this type of bearing and found they should operate between 145-185F. My handy digital temp probe showed the bearing stabilized at around 132F on high speed. I can live with that. I have a long drive coming up this weekend, so I will find out if they are gonna make it or not!! The second plan of attack is to install a new blower motor. My research showed that almost all new blower motors are 3" in diameter. Our motors are 2-5/16" diameter. Guess what other type of vehicle uses that exact same size? Tractors!! I found a tractor supply place with two motors of close enough size they might just work. But at $130 plus shipping I figured I would give my $14 abec 7 bearings a try first.

Catalog is here:
http://www.heco.net/maincat/motors.pdf

Page 15, blowers BA4080 and BA4081 look like they will work.

I hope this helps people in need of some wind in their face during those long summer drives!!

Tim
 

· But Mad North-Northwest
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You sure your wire is connected to the correct terminal on the microswitch? From the wiring diagram it looks like it has NO and NC terminals. The brown wire from the blower should be connected to the NO terminal.

I assume this is so that when the lever is moved to max cold, the microswitch closes and switches on the extra blower. I'm just going from the diagrams here, though, so this could all be wrong.
 

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Discussion Starter · #3 ·
Since it is the only thing in the entire system that is easy to get to an verify, I will take a look at it tonight to make sure someone has not swapped it around. That would make better sense, wouldn't it?

Tim
 

· But Mad North-Northwest
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Provided I'm correct that the microswitch is tripped when the lever is full cold then, yes, that's what makes sense and what the wiring diagram says.

If you like, I can try to come up with some more difficult ideas that will require disassembling half the car to verify :D
 

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Discussion Starter · #5 ·
Sounds like I need to pay more attention to what is plugged in where on the wiring diagram. I was just tracing wires at the time I got it working. Just the fact I had found the microswitch was enough for me. My guess is it is plugged in wrong.

Tim
 

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Discussion Starter · #7 ·
The bearings are great!! But I have a lesson for the next guy.... Despite your better judgement, go ahead and take the motor apart. I took one side apart to see if I could get the new bearings to fit in the same place as the old. No dice. But while I was in there I cleaned things up a bit and removed the old bearing. I decided it would be better to leave the other side alone. These motors are not designed to be taken apart after all. But here is the lesson.... the remaining bearing squeaks!! The motor turns faster than it ever has and is virtually silent most of the time. But on some days the leftover bearing will rub and squeak. It is annoying but I can live with it as the cold cold air blows across my face.

The new bearings work great!! They are cheap, rebuildable, etc. I did not take any pictures due to my embarrassing installation. They are literally held in place with a clever arrangement of zipties. It works great but looks really bad. As far as longevity for the assembly, I looked up the working temps for this type of bearing according to SKF. I cannot remember the numbers now, but it was a good 50 degrees or so higher than what my thermometer saw before they would even be considered in the working range. If they ever did burn up, I would probably replace them with a fresh set repacked with good bearing grease.

Tim
 
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