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Discussion Starter #1
Just curious if anyone has had any luck rebuilding the blower motor instead of buying a new unit which is apparently a new design. Year is a 97.

Just started looking around, but it appears that the problem actually lies in the speed control circuit (?).

I'm good enough with electronics to be considered dangerous :D . Internal schematics of the blower motor would be great (heck, I've found schematics for the digital dash in my 85 Vette, so they gotta be out there somewhere). I'm expecting to pop it open and find everything jellied in potting compound and for any chips to have paint over the numbers, but who knows...I'll be pulling it out here in a few minutes and I'll see what I can dig up.

TIA
 

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Well, you are right about the blower control circuit contained inside the blower unit. It is expedient to change the unit as a whole as opposed to repairing it. The most likely cause for failure IS the fan speed control circuit.
 

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From what I saw when I replaced mine, it did not appear to be repairable, but I do not know enough about it to be considered dangerous.
 

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Discussion Starter #4
One of the windings is burned pretty bad...speed control could also be toast, but it might not be complete junk...
 

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If you want a blower motor to attempt a rebuild, I'll consider sending you the one from my 96 Concours(DeVille) for a small fee.
 

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I replaced one on my 1996 DeVille. When I reinstalled the new one, I installed the old aluminized cover long with the new aluminized cover to try to keep the heat down.

The speed control circuits in the old unit were burned badly. By this I mean that the main heavy duty 1/4 wide by whatever thick connections had been melted. I figured it was time for a new unit.

So far--6 months no problems. It is a lifetime warranty part and now that I have replaced one and learned that the engine does not need to be dropped/lowered, I'll never need to worry about buying another unit.....

Good Luck
 

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I was wondering if you ever found the schematic for the blower. I was looking for the value of the 2 big resistors inside. Thanks
 

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I took my broke 1996 blower apart last week to try to repair it. Had a burned out Transistor "M8966" but could not find cross reference locally. Motorola went out of business in 2004 . Also you have to drill out the mounts that the circuit board is mounted on in order to service the circuit board.(it spins with the blower wheel). If I could get the transistor locally I might try it, but it is to much trouble ordering online with high shipping costs for a sub part that might not be right. This motor is a "high quality" motor compared to the replacement motor but electronics have changed so much from 1996 that you cannot get parts anymore. All the components on the circuit board are labeled but you first have to wash the board in tri-clor to remove the sealant before you can read them. new motor circuit is on an IC. (on one chip that is not marked!) By the way the new replacement motor went in in 30 min with no problem. BUT....... the old style blower took two hours to get out by finally destroying the plastic wheel! :banghead:
 

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Surrey-20111216-00260.jpg I just disassembled a three piece ( probably 4-season type ) I think your'e on the right track. This blower was intermittent, so I did go the usual route thinking it may be bad wiring,gnd.,controls,etc. But since I had another Caddy I made a ten foot long three wire cable and used the controls of one car to operate the other ones Blower. Controls OK. I now knew it was the blower. Anyhow, I looked really close at every component on the curcuit board ( before I read this Question ) and the only thing that looked suspicious was one of the two resistors. these are made to take high current and they both looked like they get fairly hot. One actually looked like ( over time ) could have heated and reheated the solder connection on the curcuit board and possibly made a cold solder joint ( it's very dull and rough ). I'm going to attemp to resolder it. If that doesn't work I'll replace it. By the way, It's a 3 ohm, 5% tolerance. I've taken some pictures ( beleive it or not through a magnifying glass/lots of light with a cell phone ) Thats how I read the value of the resistor.
 
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