Wanitive

Thanks for the pictures and advice @bclexus . So do you think I should take the back of the seat off with the seat still in the car and try to adjust it and see if anything inside moves?
@peasodos was the one who gave me the confidence to do this swap in the first place (and if nothing else I guess I traded lumbar for heated/cooled, which I probably would have agreed to if I'd been told that up front, but still...), hopefully they will be able to tell me what's going wrong here.

I felt like I made some progress by finding those fault codes. Although they didn't really tell me anything I don't already know, they migh be more significant to someone who knows what they're doing (i.e. not me).

bclexus

@Wanitive - If I was troubleshooting the seat I'd power it up anyway I could (which might only be possible while it's in the car) in order to test each of the seats positions/actions. I would want to see that each motor worked and what action it is to perform - and how that action is supposed to be accomplished. These seats are very complicated with lots of motors, cables and linkages. As complicated as the seat is - lots can break and go wrong with them!

Of course ideally the absolute best testing procedure would be to have a 'test bench' with a live wiring harness and related connection plugs readily available and powered by a car's system which would include the seat's memory - but since that's not possible, you're going to have to work with what you have.

EAST

You in the Orlando area? If you can wait a week or two, I might be able to meet up with you, at least to get some basic diagnostics out of the way. I have Techstream, a power supply, and some basic tools. Not promising anything, more a second set of eyes.

Can hash out details in PM if you're down.

As a side note, if you're doing more upgrades or just general diagnostics, I'd recommend getting a bidirectional scanner (or Carista). These cars have a bunch of modules that you can do basic tests with (the 16/18 way seats have the position control ECU) that help with diagnostics.

Wanitive

@EAST I am close enough to Orlando, I'll PM you.

I have an ODBLink MX+ and I used the free trial of Carista to scan and the drivers seat showed 4 faults: B2655 - Cushion Lenght Sensor Malfunction; B2659 - Side Support Sensor Circut; B265B - Lumbar Support Sensor Circut; B265c - Pelvis Support Sensor Circuit. I just don't know what else to do with that information unfortunately.

Wanitive

Huge shoutout to @EAST for spending his entire MLK day trying to figure out what's wrong with my seat! He'll post about what all he tried, but in the mean time he put power directly to the motors in the seats to get them positioned how I want. He also upgraded my puddle lights to LEDS.

Can't thank you enough man, I really appreciate all that you did today!

EAST

Nice to meet up with you, @Wanitive .

Here is what all was checked:
- Established communication with Position Control ECU. Attempted to command the problem motors via Xtool and Techstream to move each of the motors. Relays would click 1-3 times but problem motors would not move. Working motors did move when commanded from Xtools.

- We tried to find in Techstream some way of re-initializing the module, but couldn't find anything in Utilities.

- We disconnected the connectors of some of the problem motors. The pelvis and lumbar motors are accessible removing the back part of the seat, We applied 12-14V via a power supply to pins 1 and 4 (corresponding to the thicker gauge wire on the connector). The motors did work, so motor itself was not the problem. We went ahead and set the position of the lumbar to a comfortable position (apply voltage one way, and reverse the position of the pins to make the motor go the other way).

- We checked the continuity between the motor connectors and the corresponding connectors going to the Position Control ECU assembly. Continuity was good.
Lumbar Support motor - Violet wire to connector d4, pin 5 and tan wire connector d5, pin 3 are the motor wires.
Pelvic support motor - Red wire to connector d3, pin 4, and blue wire connector d3, pin 2 are the motor wires
Thigh extender motor - Grey wire to connector d4, pin 6, and light green wire to connector d4, pin 4 are the motor wires
Reclining motor - Violet wire to connector d2, pin 8, and green wire to connector d2 pin 10 are the motor wires
Lift motor - Yellow wire to connector d2, pin 2, and light blue wire to connector d2 pin 9 are the motor wires
Tilt motor - Red wire to d2, pin 7, and White wire to connector d2, pin 4 are the motor wires
Slide motor - Blue wire to d2 pin 6 and Pink wire to connector d2 pin 3 are the motor wires.
Side bolster motor - Violet wire to d3, pin 3, and pink wire to connector d3, pin 6 are the motor wires.

The motor wires are the thicker gauged wires (maybe a 16) compared to the thinner "signal" wires. All motors will have a brown ground signal wire and a sensor/Vcc wire (or different colors for each motor).

- From here, we checked the signal voltage from the ECU. While the motor side connector was disconnected from the motor, we measured for 5V from the signal wires (the two inner, thinner gauged wires on the motor connector). They would only have 5V momentarily when pressing the respective button on the seat side panel. Basically, it would only have the voltage as long as the relays were clicking then go back to 0V.

- It was similar when connecting the motor connector back on to the motor, and measuring the Vcc voltage between the non-brown inner wire and body ground. It would be 5V momentarily.

- We opened the Position Control ECU module, but didn't see anything burnt or out of place.

So for now, manually adjusted the needed motors, and buttoned everything back up. Consensus seems to be a bad Position Control module, but it just seems weird that it'd go bad for both pairs of seats for the same set of motors, so it's still iffy if that is the actual cause. But the other thing would be the motor sensors (?) themselves going bad, but same doubt of why the same motors on two pairs of seats?

It's funny, the 10-way seat just powers everything through the side switches, and the motors only have 2 connectors (for power). The 16 and 18-way seats have the modules, and all the motors have sensor wires in them. Must have been done for a reason.