I been noticing for awhile that when i push the Tow/Haul mode button on the shifter, it does not light up in the dash like it used to, and it does not engage into the Tow/Haul mode, but if i drop my trans. down to "3", then hit the button, it works and the light comes on and it works like it should, but it's not consistent. Sometimes it works w/o dropping down to "3", and sometimes it doesn't. Same when i go to take it out, i have to put the trans. back into "3", hit the button to take it out of Tow/Haul, then shift it manually back to "D". Any idea's? Switch, sensor, something dirty, what? Anyone had this happen as well? Its an '03 Silverado 1500 4X4. Thanx for any info in advance, Jim

 

I don't know for sure, but it sounds like a bad connection. When you move the shifter it must make the connection allowing the button to function. I would start by checking for loose wires/connectors.