3 years of intermittent "Service 4WD" light. I pulled the dash and switch using no tools. I pryed the cover off the switch with a small flathead screwdriver. The posts looked fine to the naked eye, but under a microscope, the solder on the posts were definitely fatigued. A quick relfow with the solder gun was all that was needed. I put it back together and it works just fine! $0 spent and only 10 minutes of my time.
I have an 03 Silverado, Service 4WD Light on. The 1st time the mice chewed the wires by the transfer case. Fixed the problem once the wires were fixed. The 2nd time I checked all fuses, OK, checked all wiring OK, getting power everywhere. I pulled the 4wd switch out, popped it apart since many guys suggested the connector bread and to put a drop of solder on it. Not my problem all my lights were burned so my switch was fried. I bought a new switch $88.00 and nothing worked so I disconnected the battery for 15 minutes and it reset the system and everything is OK. So try the battery disconnect first and save some money but in my case my switch was fried anyway. Good Luck
i have 99 silverado ext cab lt. the service 4wd light is constantly on. before it would switch on and off. ive changed the switch out and drained the old oil out and put new oil in...the light stays on now.. why is that?