When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Good post. Makes me wonder why my forward and backward switch sometimes goes to sleep ... do the switch instructions have to go through the controller board on the way to the motors? Worth it to flip the seat over and try reflowing the solder one nice spring day ... might even wake up the snoozing lumbar up and down adjustment ...
Tom I guarantee that is the problem - all go through the memory box.
__________________
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission? George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
I dealt with this same issue today, thinking it was a problem at a connector, but ultimately deciding it was likely bad solder joints in the power seat controller.
Symptoms were:
Seat/mirror memory switch #1 backlighting worked only intermittently.
Sometimes all three memory switch back-lights would turn off. I only realized yesterday that the power seat motors also were inoperative when this happened.
Today, I spent a lot of time jiggling cables around (first with the seat in the car, and later with the seat removed) and couldn't pinpoint where the discontinuities were occurring. Finally, I noticed that just tapping the power seat control unit would cause the intermittent behavior to change (start working or stop working).
Did you know that the cable to the seat is just long enough to let you test it outside the car?
Got the power seat control unit (928.618.134.02) off the seat (disconnecting all the connectors takes a while!) and opened it up.
As you can see from above, connector #1 is for power and ground (terminals 30, 15, 31). Let's take a look at the solder joints for those pins:
Well, those are crappy solder joints! No wonder there was intermittent power loss!
Repaired those; here's the "after" photo:
And how about that intermittent backlighting on memory switch #1? Here's what the solder joints for the pins for connector #15 (which, with labels like "PL1", "PL2", "PL3", "PT", and "WL" sure looked likely to be related to the switch backlights; "PL1" is probably the switch #1 backlight, and that corresponds to the bottom right pad below) looked like:
Fixed those, too. Went ahead and re-flowed all the rest of the connector pin joints. Most of the rest didn't look so bad.
FWIW, I was using a temperature-controlled soldering iron at 750 °F and added just a little bit of old 60%/40% tin/lead solder (the latter based on the assumption that this old PCB was probably using similar solder) to each joint, mostly for the benefit of adding a little rosin to assist with flow.
IMHO, these PCBs were likely improperly manufactured.
Oh yeah... everything worked perfectly upon seat re-installation.
Last edited by Ed Scherer; 04-14-2017 at 03:04 PM.
I dealt with this same issue today, thinking it was a problem at a connector, but ultimately deciding it was likely bad solder joints in the power seat controller.
Symptoms were:
Seat/mirror memory switch #1 backlighting worked only intermittently.
Sometimes all three memory switch back-lights would turn off. I only realized yesterday that the power seat motors also were inoperative when this happened.
Today, I spent a lot of time jiggling cables around (first with the seat in the car, and later with the seat removed) and couldn't pinpoint where the discontinuities were occurring. Finally, I noticed that just tapping the power seat control unit would cause the intermittent behavior to change (start working or stop working).
Did you know that the cable to the seat is just long enough to let you test it outside the car?
Got the power seat control unit (928.618.134.02) off the seat (disconnecting all the connectors takes a while!) and opened it up.
As you can see from above, connector #1 is for power and ground (terminals 30, 15, 31). Let's take a look at the solder joints for those pins:
Well, those are crappy solder joints! No wonder there was intermittent power loss!
Repaired those; here's the "after" photo:
And how about that intermittent backlighting on memory switch #1? Here's what the solder joints for the pins for connector #15 (which, with labels like "PL1", "PL2", "PL3", "PT", and "WL" sure looked likely to be related to the switch backlights; "PL1" is probably the switch #1 backlight, and that corresponds to the bottom right pad below) looked like:
Fixed those, too. Went ahead and re-flowed all the rest of the connector pin joints. Most of the rest didn't look so bad.
FWIW, I was using a temperature-controlled soldering iron at 750 °F and added just a little bit of old 60%/40% tin/lead solder (the latter based on the assumption that this old PCB was probably using similar solder) to each joint, mostly for the benefit of adding a little rosin to assist with flow.
IMHO, these PCBs were likely improperly manufactured.
Oh yeah... everything worked perfectly upon seat re-installation.
This was perfect..Just read this and tried re-soldering...actually worked....kind of...passenger seat came out fine, everything works...drivers I only have memory function #2 working...any idea which plug it is that controls this so that I can focus on that one?
Know this is an old thread...just hope there is someone out there reading it..lol
02-18-2013, 05:58 PM
George Layton March 2014
