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Anyone who knows me will know how gremlins enjoy irritating me. My drivers side seat controls have gone wild. I will attempt to describe it:
Switch to move seat forward- Seat moves forward (have to repeatedly click switch on and off and will move in increments)
Switch to move seat backward- the rear vertical goes up.
Switch to raise front vertical- front raises.
Switch to lower front vertical- seat goes down and backward.
Switch to raise rear vertical- telescope steering goes forward and seat rear vertical goes down
Switch to lower rear vertical- telescope steering goes backward.
So using the schematics for 1) Memory seats w/telescoping column and 2) tilt/Steering column I still CANNOT makes heads or tails. I do not think it is the switch. I have opened it various times, cleaned and inspected for solder issues. There are no parts that would short or wear out. As the switch should have NO connection to telescope column but is activated by it, I suspect a bad relay in the SCM. I have opened it also and have not been able to find any suspect joints or issues.
I would appreciate anyone's assistance on this, especially you electronic whizzes out there..........Bill.
Wow.....views but no comments? Really? Well I'll add some more anyway. Suspecting a bad relay in SCM I obtained another SCM. When I plugged this one in, NOTHING happened. Not a sound, not a click, NOTHING. I put my original in and it continued doing the same crazy motions as before. Do SCM + T need programming?
Thanks for the look Bill! I have taken the switch apart twice. No sign of corrosion. Looks pristine. I have used a set of loupes to inspect the board closely for cold joints, cracks and have found none. Tell me about these contacts Bill. They don't seem to have any metal, just a small contact area of soft rubber perforated like a salt shaker. When each of them is manipulated up or down they just pivot over the top of the contact on board. It's an odd set up, but simple. It makes for a board with very little physical movement of components.
I'll take a closer look with multimeter tonight. You think it more likely the switch as opposed to SCM? Seems to me more likely SCM only because the telescoping steering wheel is involved...and I'm having difficulty tracking it with schematics.
Last edited by BadMedcn; Sep 25, 2014 at 08:08 PM.
Reason: Additional info
So....as per Bill's rec I pulled the switch apart and it checked out fine. Since I am in the process of putting new skins/foam on seats I pulled off the switch on passenger seat (same as driver side # and all) and plugged it in. Same thing. Apparently the replacement SCM+T was dead so they immediately sent me another. This one worked but my seats STILL don't. So it ain't the switch and it ain't the SCM. I switched the circuit breaker and fuse. Checked and cleaned the ground (G205).Nothing I have done has made a difference. Interestingly, the passenger side works flawlessly. Any thoughts?
There have been no DIC codes. When I unplugged power to SCM I did get a "No Communication" but that was deleted and then seat power restored and that resolved, obviously only secondary to disrupting power.
Thanks a lot Bill! I had a feeling I was going to get stuck chasing the wiring. I'll post as soon as I finish.
So......I have narrowed the seat issue to my BCM (if you can believe that!). My last major bout with gremlins last year resulted in me replacing my BCM on a whim. It didn't solve my issue. I did have to go through the so called "handshake" protocol to sync the new BCM with my car. The car ran but continued to throw codes....that was finally fixed, but that's another story that has NOTHING to do with OEM. So this morning I thought I'd hook up my original BCM and then try the seat. Lo and behold, all functioned perfectly!! I have yet ANOTHER BCM that I obtained when I obtained an old wiring harness from a same year car some time ago. All three are the same part number, so identical. I plugged that one in and got the exact same craziness as with the replacement. So, given that two identical BCMs cause the same issues with the seat, and the original works perfect tells me several things:
1. The BCMs are good
2. The BCMs are somehow in need of programming for seats as well as the security sync.
3. I have no idea how to do that.
So now I need input from Bill Curlee and anyone else who is aware of this BCM/SCM relationship. Anyone?
Thanks Voodoo,
The shop manual has the same sequence and it works. Problem is that apparently all of the RPOs the car came with are "enabled" or programmed into the BCM. So the above sequence serves only to set the password for the VTD (Vehicle Theft Deterrant) but does nothing for the fog lights, head lights, memory, TCS, and a few others. This part will require a Tech2 I'm afraid. My only current issue is the seats with relation to the BCM. The other above mentioned RPOs are functioning normally. I found this explanation buried in the shop manual:
The BCM requires programming as noted in the above post. Both my replacement BCMs came from apparently NON memory seat cars. To function properly the BCM needs to be programmed using a Tech 2. Five minutes after plugging in a Tech2 I have functioning seats again! A lot of work could have been avoided had I been more aware of the actual functioning of the system involved. The shop manual has been repeatedly a life saver. Do yourself a favor before getting into pesky electric issues and understand the system involved by reading it in the manual. It will likely save you time and money.
Thanks to those who chimed in suggestions, the forum continues to be a tremendous resource and teamed with the shop manual can be unbeatable.
Seat Gremlins
