Bit of an issue here guys, I've got a 2008 Silverado LTZ (208k miles) with problems in the heated seats and the driver power seat adjustment.

The seat heater controls (upper and lower buttons for both driver and passenger seats) light up when the button is pushed, then after about 2-3 seconds go out, and the seats do not warm.

There is two clicks in the Memory Seat Module under the drivers seat when any of the buttons are pushed.



The power seat controls for the drivers seat are also on the fritz. When trying to move the bottom or back of the seat, the motor will just kind of "bump" (maybe a quarter of a second) and then will stop moving. About 3 seconds after it stops, I am able to press the button again, and it will bump and make another small adjustment. The passenger seat power controls work/move fine.

Lumbar controls work fine on both seats as well.



NOW... I have been troubleshooting the issue for about a week now, and I'll list everything I've done/found.



I've tried disconnecting the seat heaters individually, no change to system operation.

I've disconnected as many of the seat motors as I could get my hands on, no change.

I've disconnected the sensor on the adjustable pedals, no change.

I've looked at every plug and connector under both seats, and I haven't found any burned or melted plastic or connectors.



I have been able to get the lights on the heated switches to stay on after disconnecting the forward inboard plug on the Memory Seat Module under the driver's seat, but the seats do not actually heat up.

(If anyone has a good schematic, or knows what wires that plug goes to, I'm guessing those are the circuits that are shutting off the system, any help would be appreciated.)



I have also been able to "trick" the lights on the door switches into staying on be continuously adjusting the foot pedals, but as soon as I stop adjusting the pedals, the lights go back out. The seats never warmed during this operation, just lights.



Any nods in the right direction would be GREATLY appreciated, I didnt notice the issue until this cold weather started moving in, and now it's a problem.haha

Thanks

 

You might have a broken element in the heating element in the seat..I've seen it a few times at work..If it doesnt see the continous loop in the element after a few seconds it will kill the power, its a kind of protection mode. But you would have to take the covers off the seat which are pretty easy in those models to do in the truck.

 

Turns out it was the under-seat module. It was replaced, and everything has been working for for about a week!