I have a neighbor who has an '05 manual TL in which one of the backup light sockets has no power going to it. He has used a voltmeter and a new lamp to prove this and it shows nothing.

Has anyone seen this and if so, what might be the cause?

 

is he missing the +12 or the negative? the connectors just splice right there in the trunk so if he can work a voltmeter, he can trace the wire.

 

He told me that there are wires going to the light, but he says he doesn't show a voltage. He said he tried the lamp from the good light and it did not work in the bad light. My first thought was perhaps his switch from reverse gear (shifter) has failed.

I am going to send all responses I get to him via email so he will have something to look at. Thanks.

 

I have a multi meter, can you be more specific on how to determine whether I have lost the +12 or the negative?

 

If only 1 side works the reverse trigger is working. with a multimeter, connect one side to the car chassis( ground) and search for +12vdc at the light socket. If you do find +12vdc on one side, the other side is ground so check resistance and it should read 0. If you dont find +12, still check resistance to make sure you have a ground. Sometimes, a plug can get hot and melt the connector loosening the metal pins. check for that too. And im not talking about where the bulb plugs into, im talking about the actual pin connector. Let me know what you find. and since you are already there... if you dont find either voltage or ground, trace the cable, it literally splits right there. you can move the whole harness and ensure its connected.

 

Thanks so much for jumping in on this. I know he is really going to appreciate your suggestions and help.

 

Ok I have the +12 on the side that is not working. I also checked the resistance from the negative to negative and I and getting a zero reading ( like an open circuit) not like when you check a fuse and the needle goes all the way up.

 

I did a little modding to my back up lamps i will show you guys latter, but the back up lamps have a single wire that powers them. it goes to one light then jumps over to the other. so if you have power (+) on both sides then its going to be a ground issue. make sure you pull both bulbs when you check this cause you might be getting + feed back through the bulbs. Best tool that i seen to check these issues is a power probe check out powerprobe.com... i used one of these a while ago and i had to get one of my own right away. saved so much time its paid it self off many times.

 

all the grounds that are on the trunk are bundled up behind the carpet lining by the gas filler.

 

Thank You everyone, The problem was as you expected a faulty ground wire. Rather than locate the break I just routed and soldered a new ground wire and things appear to be working fine. Thank You All Again!!!

 

False alarm, Both lights now work when the trunk is open. When the trunk is closed the right side goes off ( note that this was the side that was working before. Back to the drawing board!!!

 

Something is loose in there. I'd just check the ground and fcix that before something else occurs.