Hey, I have a 1999 Silverado, truck had a 4wd 4l60, now has a 2wd 4l80. I removed all 4wd components. I never used the 4wd so when trans went, I wanted to upgrade to an 80 an didn't want 4wd anymore. So anyways, I'm trying to get the service 4wd light to go off in the message center in gauge cluster. I'm not sure if I can swap to a 2wd bcm or if there is even a difference in the two or what I need/can do. Any help would be greatly appreciated. Thanks

 

Try unplug your transfer case control module under the dash and see if it goes off

 

Tried unplugging the transfer case module today, didn't make light go off. Getting really bummed now, I have no idea what else to try.

 

 

Ha ha I have seen that video before and was thinking of it before you posted it.

But seriously, GM had some bad solder in those years that could be the culprit. See if you can find someone with a functioning system of the same year and see if they will let you swap the switch in the dash to see if it temporarily corrects the problem. If you cant, remove the switch and resolder every connection on the back. I had a 99 Silverado and the 4WD would not work. I resoldered every connection and it work fine again.

 

You may need to have the PCM reprogrammed to tell it, it no longer has 4x4.

 

I resoldered the connections on the back of my switch and never had that light come on again. Just melt them and let them cool. Voila.

 

Remove 4x4 Fuse in underhood block. Disconnect battery for 30 seconds. Voila! no more 4x4 light or message. As far as your truck computer is concerned it is now a 2wd.