Lumbar seat controls. Problem located.

[4PASNU]

Since I've got my car back now I'm slowly going through all the little problems and getting them fixed. One problem is the lumbar controls don't work. The forward, backward, up, down still works but the legs, headrest, lumbar doesn't. I decided today was the day to track down this problem so I began tearing into it. I started under the seat checking voltages and tracing wires. The problem let me to the control panel. Good in but nothing out. I figured it's just a bunch of switches so the problem should be easy to isolate. I was right. Take a look at the picture below! If you look in the upper left corner of the board you'll see a foil run that has a problem. It melted right open. There is probably a 1mm gap in the run and small burn marks above and below the run. Luckily I have micro-miniature soldering guys that work for me so I should be able to get them to fix it. If they can't fix the run I guess I'll just have them solder in a jumper. So hopefully my lumber controls will be back online in the next day or two.  Just thought I'd pass this on as something to look for if your seats don't work.

[Jeff M]

That is the fusible link for the motor :lol:  Just kidding, nice find and info 8) , will keep it in mind when people email me for fixes!  

I have seen water that gets onto the door when it rains (window open for drive-through etc, or when getting in and out of car in the rain) ends up corroding the circuit traces on the Mirror Control taking the traces out/open.  Like you a little solder and maybe some caulk (for the Mirror Control only) and back in business.  I also have seen too many window motors with burnt spots that makes them either hang at the bottom and/or have a weak spot when they go up and down, so to avoid this happening to those not messed up yet/dead even, I take out that damn chrome nub that holds it in the down position and learn to open it like most people do, as far as I want without it going all the way down on its own :lol:   TSTE seem to have better circuits as mine does not have this crude chrome nub :evil: Nice to get a few of these little problems fixed, then more time enjoying the ride!!

Jeff M

[4PASNU]

Well, I thought I had the problem fixed but now there is something else wrong.  I had my guy fix the foil run on the circuit card and they did a fantastic job.  I was excited to get it home today and plug it in to test it out.  Well, I hit the switch, heard the pump start, and about a tenth of a second after it stopped and wouldn't do anything else.  Driver and passenger, all functions not working again.  No blown fuses, no visual damage.  Now it's back to troubleshooting tomorrow to see if I can find what else went bad.

[4PASNU]

OK, I think I might have finally isolated the problem, hopefully for real this time.  I found that the foil run that was repaired actually opened up again so I decided to just solder in a wire to correct the problem.  That kind of worked.  The deflate side of the house worked but inflate was not working.  I troubleshot it down to the control panel once again and found another foil run that had opened.  At this time I knew there had to be something else causing the problem since I knew that had just happened.  I needed to isolate the problem between the lumbar seat switch panel, the seat control module (under the seat), and the pump (also under the seat).  I disconnected the lumbar seat switch panel and jumpered between input power and the inflate activation wire, no good (lumbar seat switch panel OK).  Then I opened up the seat control module to manually activate the relay to see if the pump would turn on, it did (pump good).  So now I knew the seat control module was the culprit.  Just for fun I tested the inflate relay and found that the thing is shorted out.  The other two relays read 70-75 ohms across the windings.  So now I'm in need of a seat control module, anyone have a spare?  gmpartsdirect.com wants $57 for one but I'd rather get a used one if possible.  I'll post this over in the For Sale topic as a WTB so it will get some more attention.  I really want my seats working again.