Quote:
Originally Posted by vipercrazy
sorry to bump this thread, but it seems to be the main dicussion on this.
i just re-soldered every joint on my ccu and it performs the same task as before, just opening vents, letting heat through on defrost, but still no blower at any setting.
im not sure if i have to get inside this unit, because it explains three ccu boards but only has pictures of the unit assembeld.
what still needs to be checked on this board before i move onto other possible problem areas on the car?
my heat/ac has worked for multipe months at a time perfectly so this makes me think its something electical.
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Disassemble the unit and check for cracked joints. There are two "wing" boards that contain the cable plug pins and are soldered to a mainboard forming a shallow 'U' shape. Then, there's another daughter board stacked with the main board -- so there's really four boards in all. I recently did mine and found that the solder joints to one of the wing boards were broken clean through.
Incidently I did a bit of root cause analysis on my CCUs solder joint failure (not that I'm necessarily qualified) and concluded that the wing board in question was soldered on at an angle, and then flexed to make the connections meet at the far end. A poor design (solder as mechanical attachment) aggravated by poor manufacturing (a flexed wing board adding additional stress). The CCU unit plastic case provides the gross mechanical strain relief for the wings, but this kind of stress didn't wasn't something it could provide the strain relief for. This might explain why these things fail if others were manufactured incorrectly like mine was.
Others have reported the switch solder joints to have failed, but mine were fine. All the cracked solder joints of interest are
inside the plastic case, and there's a couple of stacked boards, so just getting to the bottom of one of the boards isn't enough.
I took copious pictures of the CCU disassembly procedure, problem, what cracked solder joints look like, etc., but I don't have time to upload them tonight (sorry), I'll try to get to them tomorrow.