Just bought a 99 Tahoe 4X4 OBS and replaced all the dash lights, now when I turn the key to run all the lights illuminate as normal but then the ABS and Security lights don't go completely out, they just dim way down. Any ideas on why they would just dim and not go completely out? Thanks in advances.

 

What kind of bulbs did you install?
When you plugged the circuit board back in , could you maybe have pushed out or lost a connection at that plug?

 

I used LED's on for all of the bulbs. I pulled the dash back out and swapped those 2 back to normal bulbs and they go out as normal. My guess is there is a small amount of current staying applied to those circuits which is enough to dimly light an LED but not enough to light a standard bulb.

 

You got it. Sometimes LED do not play well when retrofitted into an incandescent circuit.