Here is what I ran into with my 04 suburban. I chased that light for a year, New everything.
What I found was the dimmer switch was causing a short through the instrument panel. Confusing the body control module and keeping the tmps light on.
I took the light switch out, took it apart cleaned all the old grease and grimeout of headlight switch as well as the dimmer switch. Put it back together with a some new dielectric grease it. I put the same dimmer switch back in. Hit the key and the light went out after the start up bulb test and no more service tire monitor.
I know that this sounds unreal and why would the dimmer switch effect the tmps? I asked the same questions. I found the dimmer switch code using my tmps scanner programmer. Thought oh great new problem. Fixed that pro lem and it fixes my tmps system. Good luck to all.
