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Is it possible to fix Door control module? (Electronic gurus)
I found that my mirror blinkers are not working at all due to the driver side door DCM acting up, being faulty on my 01' S430. Every single function on the DCM works but I am getting no voltage whatsoever on the two pins + and - responsible for sending voltage to the mirror blinkers. Those are pins 6 and 7 illustrated. I opened the DCM and I am 'alright' with electronics I can do soldering and stuff, understand resistors and capacitors, but I cannot find really anything wrong on the board. I don't see any water damage nor obvious blown or puffy capacitors. Take a look for your self but, I really can't find anything. I did some random resistor measurements and continuity measurements also. Does anyone know where or how to look or have schematics?
I had a 220 with the same problem, and the issue was poor soldering on the wiring for the blinkers. If the output from the DCM is similar to other lighting circuits, then it will not produce a voltage unless it is properly loaded (by the mirror LEDs, in this case). You could test that by seeing if the passenger-side DCM outputs a voltage in the presence of an open circuit.
I believe a properly functioning DCM does output around 12volts right at the pins, regardless of load presence or not. I've ruled out any wiring issues or led lighting issues from the dcm to the mirror housing. One test I did was just plug a plain ol' 12v dc adapter to the pins 6 and 7 on the connector cable on dcm side and everything lights up.
Located just millimeters from pins 6 and 7 is some sort of transistor. I'd follow the printed circuit traces from pins 6 and 7 and see if they go to that transistor or another semiconductor. If they do go to the transistor and you aren't sure how to do check it, then post whatever you see printed on the transistor here and I or someone will reply.
Right I was thinking about those, but I don't know how to test them. I'm assuming they have to come out for proper test. I already tested the teeny tiny resistors next to those pins and they return good results. Pin 6 and 7 don't go particularly anywhere on the pcb board. Here's more pics:
Those are "bipolar junction" transistors (BJTs) of "PNP" polarity. You can test one with a meter that has a diode check function, and this ought to be done with the transistor removed from the board.
With the (-) lead on the middle pin (the transistor's "base") and the (+) lead on either of the other two pins ("collector", "emitter"), the meter should show .7 volts. With the leads reversed or on the emitter and collector the meter should show infinite volts. Also, the resistance between any pin and one of the other two pins should be in the mega-ohm range.
You are correct , they are PNP. I removed one of them, had negative lead on base and positive on emitter, shows .74 on the diode check. Negative on base and positive on collector shows the same. It seems like the one I removed is 'good'. These are so tiny. It didn't even seem possible to remove it without damaging it. Tough to unsolder. I'd probably have to buy another one of these and solder it on, toss the old one. They are very cheap.
I have "exactly" the same problem on mu S320 (W220).
Did you manage to solve it?
If so, what was the solution?
Regards,
Jeff
I didn't find a method to fix the board, and I just got a some replacements on ebay until I found one that finally worked for the mirror blinker signals. I had to go through at least two used ones until the third one I got worked. If I had to GUESS, I would guess that replacing some capacitors on the board may fix something. The w220's are almost 25 years old so 25 year old capacitors are very questionable at that point.
I didn't find a method to fix the board, and I just got a some replacements on ebay until I found one that finally worked for the mirror blinker signals. I had to go through at least two used ones until the third one I got worked. If I had to GUESS, I would guess that replacing some capacitors on the board may fix something. The w220's are almost 25 years old so 25 year old capacitors are very questionable at that point.
Many thanks for confirming.
I have just done similar and purchased a couple of used modules on eBay.
Fingers crossed!!!
How about the "fast blinking" with the aftermarket LED bulbs.
Did you find a resistor value to avoid the problem (and associated diagnostic codes)?
If so, where did you physically install them?
Many thanks for confirming.
I have just done similar and purchased a couple of used modules on eBay.
Fingers crossed!!!
How about the "fast blinking" with the aftermarket LED bulbs.
Did you find a resistor value to avoid the problem (and associated diagnostic codes)?
If so, where did you physically install them?
Kind Regards.
I recall a 150 ohm, 5v resistor in parallel works fine and does not fast blink or throw an error . I agree with tusabes that leds may not work right, but they've worked fine for me so far. The only issue is sometimes the whole strip doesn't work, and only some leds on the strip light up for some reason.
I recall a 150 ohm, 5v resistor in parallel works fine and does not fast blink or throw an error . I agree with tusabes that leds may not work right, but they've worked fine for me so far. The only issue is sometimes the whole strip doesn't work, and only some leds on the strip light up for some reason.
Thanks for the expert advice ... very much appreciated.
Passenger side mirror indicator is now working again, thanks to a 2nd hand door controller from eBay.
But still have problems with the driver's side mirror turn signal.
It stays on (even with the ignition turned off), leading to flat batteries.
Same problems/symptoms exist after replacing the module.
Have checked the mirror turn signal itself using a 12v battery and alligator clips - all good.
Have also tested the wires from the door module to the to the turn signal light - no breaks or shorts.
All resolved now.
Managed to get it working with the original driver's side buttons/board combined with the replacement controller board.
Phew - glad that's over!
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