2003 GMC Denali - Both front seats have stopped working as have the passenger side windows. Driver side windows and both power mirrors work. What should I check first?

Take a look at the Fuses

After posting this I saw other topics on the same subject that didn't appear on my initial looking around. Someone said that these items were not on fuses but on circuit breakers (cant find which ones they are ) and that all of these items were run off the same ground which is located under the drivers seat. Well the drivers seat is in the all the way down position and I can barely slide a credit card under it much less a tool! LOL But anyway I have removed the plastic interior pieces around the front and rear drivers door and off the back of the B pillar and am able to slide my hand all the way under the seat and I find nothing but the black box and an air vent.
BTW when I try to roll the windows down I can hear the rear door clicking but hear nothing from the front window.
Also something that may or may not be related the past few times I had used the driver seat adjustment I swear it seamed as if the up and down on the front of the seat seamed to be working backwards. In my GMC truck if I pull up on the front of the seat adjuster the front of the seat comes up but my Yukon, the one with the problem, it was doing the opposite. When I wanted the front of the seat to come up it went down when I pulled up and up when I pushed down. Oh well hope someone has a clue.

Faulty BCM (body control module) Is my guess if you cannot find any circuit breakers. That or a bad ground.

Got it fixed. Blown buss fuse in the underhood fuse box. MBEC 1 50 amp was blown. This type of fuse is very hard to tell if it is blown. Looked right at it three or four times before light hit it just right to show it was blown. Replaced and everything works now. Toggle switch that moves front of seat up and down still running backwards though.

A simple test light or multimeter would have identified the bad fuse in seconds. Next time, here's how to quickly and properly test all underhood and underdash fuses:

https://www.askmehelpdesk.com/cars-t...tml#post252145

As I've staed here before, most of these multiple symptom problems have rarely been just a fuse or just a circuit breaker.
Before you do anything, read this:

https://www.askmehelpdesk.com/cars-t...ng-229280.html

Buy an inexpensive test light or simple volt meter and read how to use it for this simple test.

Diagnosing the fault first is paramount.
Don't spray the problem with parts until you believe that part will fix the problem.

I put a new fuse in and worked everything out just as hard as I could, one thing at a time, to see if any one item would blow fuse again and it worked out just fine.

After thinking about it Im sure I know how it happened. I was working on some rental property and needed my carpet cleaner brought down so I called my wife to bring it to me. Instead of putting it in the 40 acre field behind the third row seat, (XL) she decides to put it in the second row behind the passenger seat. In order for it to fit she had to move the passenger seat clear up against the glove box and it still was a tight fit! Well when she got to the apartment I went out to get the carpet cleaner out of the car and used my key fob to open the vehicle and guess what the seats didn't work after that. I guess the seats tried to respond to my key fob settings ( all the way back) and tried to move back but was blocked by the carpet cleaner. Mashed it pretty good too as I nearly had to tear the back of the seat to get the thing out of the car.

I know this was an old post, put I am having the same problem with my Tahoe LT 2008. Driver seat and passenger windows stopped working. We found a circuit breaker blown out. Can not figure out the reason at all this time. The breaker was changed, after two three weeks (drove about 3000 KM), the same problem occurred. We replaced the breaker, and suddenly, a strange intermittent clicking (relay sound) appeared under the dashboard. We removed the breaker and waiting for GM appointment after two weeks!!

Everything on the car is original, no single addition...

Any HELP or opinion is highly appreciated.

U didn't state if both seats stopped working, u only spoke of driver seat. I think both front seats and the passenger side windows are on the same circuit. Anyway mine blew the fuse because the seat was blocked from going backwards when trying to go to my settings for my key fob. Check the tracks that the seats slide back on for an ink pen or some other object that could be hindering the movement of the seat.
The clicking sound should be under the dash right beside the steering column this is the sub panel for this circuit.

dlbias
Thank you for the reply!
I only have the driver seat powered. The passenger seat is manual.
Also, I am very sure that there was nothing behind the seat. I actully never touched the seat control for several days before the incident. But definitely I used the passenger window.

Even the GM dealer were so surprised to hear about the problem. My appointment with them is next Saturday. I will post back the resolution for others to benefit from.

Thank you.

Yep. Just had this very same issue with our Yukon Denali. Both the seats and the passenger window stopped working. After trying to replace the 25 and then the 30 amp circuit breakers under the steering column, with no success, I saw this post and checked the 50 amp MBEC was blown. Thanks for posting this! Everything is back online and working.

I have been having the same problem but when I replaced the 50amp fuse it blows again within a few hours of use. I have actually unplugged the seat motor and heater on the drivers side in order to figure out what keeps blowing it. I haven't tried the replacing the circit breaker yet since replacing the fuse fixes the problem temporarily. I plan on replacing the circuit breaker next but I'm looking for any other suggestions.

Thanks