I have a third brake light mounted at the rear end of my hatch above the license plate area. It doesn't work. When I probe it at the plug with the assembly out, I get 12V when pressing the brake. When I put the assembly in without the bulbs, 12V on the rails. When I put *any* bulbs in, nothing. Maybe .02V, which might be from my fingers.

Any suggestions? =)

 

Burnt out bulbs. Should not handle halogen bulbs with your bare fingers, the oil from your hands cause hot spots which result in burn outs. Stop at Radio Shack and get new bulbs, the cheapest price around $1.99 last time I bought them.

 

with no bulbs in the sockets, there is no current draw through circuit except for through the voltmeter. voltmeters, especially the digital display ones have such a high impedance that current flow is negligable through the meter. without current draw, even if you had a 1MegOhm resistor in series, there would be no voltage drop.

Translation: check for corroded contacts and grounds causing excessive resistance. The contacts on the bottom of the hatch lid and on the top of the back taillight mounting panel can become quite troublesome as the car becomes older.

 

When I first got my '88 with the spoiler mounted 3rd tailight, only 3 of the 5 worked. When I put the new ones in , 2 of them still didn't work. I had to very slightly bend the contacts out to touch the contacts in the light housing and all was well. Might check that, too.