'99 Denali heated seat won't work

Pass side works fine, not the driver side. Switch has 3 positions, High, Low, and off. Neither High or Low work. Where do I start troubleshooting this problem ?

I just bought a 2004 Denali and the passenger seat didn't work. Dealer said that most of the time it is the heat element in the seat.

I have a 99 Denali also the pass side does not work. I trouble shot the problem down to the element and GMC stated that the element is sold with the seat cvr and is not sold any longer.

I have a 2000. Basically you have to take the seat out(4 bolts and 1 electrical connection). You take the seat cover partially off and you'll see where the electrical connection comes out through the bottom of the seat. You can then disconnect that. Once you have the electrical connection unhooked, you can hook for a dark spot or broken wire. My fix the first time was just cutting the bad spot out and reconnecting the wire. The second time, failed 2 years later, was a broken element WITHOUT any black spots. Much harder to troubleshoot, but I ended up testing portions of wire to figure out where the bad spot was and I took that out of the equation. Works like a charm again and took me about 2 hours.