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  #16  
Old 06-07-2008, 05:17 PM
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Location: Endicott, NY
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CCU bypass

Step #752 of my blower motor problem diagnosis was to remove the CCU, with the intent of resoldering it. After I pulled the CCU, I removed the bottom plastic plate to reveal the underside of the main circuit board. There were at least two traces where the copper had actually become exposed through the green substrate. That copper had become so corroded that it disintegrated when I touched it. So, this CCU is shot. A replacement unit is around $250, which isn't worth it to me.

So.. what I'd like to do is just install a couple (maybe one) switch to turn the blower fan on and off. On the input connector to the CCU, I measured various voltages at the pins. I measured 12V at pins 7 and 12, if I recall correctly. Question is... to which pin(s) on the OUTPUT connector do I need to apply 12V in order to get my blower motor to spin?

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  #17  
Old 06-07-2008, 06:36 PM
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If this is the 82 SD, good luck. The diagram (I tried to upload but too small to read) shows PBU C2/P5 BK/GN/WT as automatic blower speed input to the blower controller (also connects to P11 of the electronic unit for temp control), C1/P1 YL/RD as speed 1 input, C2/P8 YL/GN as speed * control, C1/P12 YL/BK as speed 2-* enable input.

Seems to me you're better off hooking up a rotary selector to the blower resistor pack.

edit - * means I can't read the cr@ppy FSM scan

Sixto
87 300D
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  #18  
Old 06-07-2008, 06:50 PM
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can you replace the trace with a wire soldered in? Check e-bay, there have been a few on there for less than $70.
maybe piece one together?
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  #19  
Old 06-07-2008, 10:32 PM
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Quote:
Originally Posted by sixto View Post
If this is the 82 SD, good luck. The diagram (I tried to upload but too small to read) shows PBU C2/P5 BK/GN/WT as automatic blower speed input to the blower controller (also connects to P11 of the electronic unit for temp control), C1/P1 YL/RD as speed 1 input, C2/P8 YL/GN as speed * control, C1/P12 YL/BK as speed 2-* enable input.

Seems to me you're better off hooking up a rotary selector to the blower resistor pack.

edit - * means I can't read the cr@ppy FSM scan

Sixto
87 300D
Sounds like I just need to jumper pin 8 on the output connector to pin 12 (i.e., 12V) on the input connector if I want the blower on full speed. This car is a beater, and not my daily driver, so this discrete setup (i.e., "off" or full blast) will suffice.
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  #20  
Old 06-07-2008, 10:43 PM
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sd's are in the pick and pulls all the time. grab a couple and get the refund for those that dont work. use yours for the core for the one that does. shouldnt cost much, maybe $15
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  #21  
Old 06-08-2008, 09:37 PM
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Finally have the blower running! This thing probably hasn't run in many years. I looked at the ETM schematics, and wound up shorting pins 6 and 12 on the connector to the blower motor regulator. This is equivalent to pressing the "high" fan speed button on the pushbutton controller.

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