I had a new rear bumper put in so I removed the old and put in some new different ones. Cut in new solid ground point. Lights function as they should. But now, I've got the "brake" light and the "antilock" brake light on the dash lit up. Fully functional, just this light is on now. I disconnected lights, dash lights go out too.

Any ideas?

Thanks

 

That's an interesting one. Get the codes and see what it's unhappy about.

 

I'm sure you checked but could you have grounded the wrong wire? Or hooked up some of the wires wrong? If you disconnect the new lights do the abs and brake lamp go out? If so I would be start checking all of the wires.
Good luck
Justin

 

Are there codes on my 89? How do I retrieve them?

 

https://www.dieseltruckresource.com/...ad.php?t=59092

Make sure you read the whole thread or you will not find the correct connector to ground.