GMC Repair: Reverse lights dont work, neutral safety switch, rear lamps

Question
Hi there!
I have a 1999 Suburban 1500 4x4.  My reverse lights are not working.  I have changed the bulbs, checked all fuses and replaced the neutral/safety switch - still no current.  I've noticed a couple of quirks with my stereo - seems like a short, but maybe a ground problem?  If it is a ground, is there more than one ground?  I read your email about the left/rear ground, but didn't know if there are others.  Also, if its not a ground problem, what else could it be?  Any help you can offer would be greatly appreciated!

Thanks,

Willow Ann

Answer
Hi
You'll need to check and see if you have power (key on engine off) on the LIGHT GREEN wire at the Trans range switch.
If so, check it at the rear lamps, same wire LIGHT GREEN using a GOOD GROUND.
If so connect your test lamp between the LIGHT green and the BLACK at the connector for the rear lights.
IF the test light lights the rear lamp bulb holder is at fault.
If it does not, the ground is the fault.
IF you do not have ANY power on the LIGHT GREEN wire, check the TURN B/U fuse. Make sure it is getting power.
If you get power on LT GREEN wire  at the switch, but NOT at the bulb holder , the LT GREEN wire is your fault between the switch and the bulbs.
Thats my advice.
I Hope it helps
Good Luck
God Bless
Pawl