View Full Version : Lumbar Support Switch - intermittent

11-12-2015, 06:37 AM
Fixing the niggly stuff I've neglected over time:
How do you actually diagnose the switch, I quickly played around taking some resistance and voltage readings which further boggled my mind, dunno maybe it was late.
As far as I can tell, it has a constant non switched 12v fed into it and gnd. Pins 1, 3, 5 not much of a clue to diagnose.

My switch intermittently works if I wiggle it around or press it billionty times. Are they fixable?

Looks like this:
http://www.ebay.com/itm/Audi-A4-b5-Seat-Lumbar-Switch-/121809474423?hash=item1c5c691377:g:uJwAAOSwF1dUNQ8 g&vxp=mtr

11-12-2015, 07:27 AM
Pins 1,3,5 will be the output wires to the motor, most probably. They should probably be energized a certain way in one position (maybe + to pin 1 and (-) to pin 3), and the opposite way in the other position. Not sure what the 3rd output wire is for. I would think 4 wires total would be enough. A diagram would be the first step. Can't tell if it's right or wrong without knowing the expected behavior.

Does sound like the switch is probably bad, though. You should buy that one ebay. lol

11-12-2015, 10:43 PM
I'm wondering if I can open this one up and possibly fix it. It is starting to happen on the other seat as well (works 80% of the time either way).

From memory in certain positions (not neutral/0) i'm only getting about 250~300mV (+ & -). The weird thing is no matter what state I have continuity which doesn't sound right at all? Really made my feeble mind blown. Do you have a seat wiring diagram handy by any chance?

11-13-2015, 07:28 AM
If no load, current and voltage will pass right through if having positive and negative on device (motor). Once there is a load on that device then amp draw and voltage is taken, making the two potentials complete.

11-20-2015, 05:05 AM
Tell me where to stick my poles, not so flash with electrics. lol.
From what you're saying I need to remove or unplug the switch from the motor to properly diagnose it?