license plate light not working

[cody818]

few days ago I removed the rear bumper to work under the car (86 930) and now I can't get both license plate lights to work.

Both bulbs and fuse #7 from second panel looks good. What else I need to check? Both lights was working before taking the bumper off.

How do I check for power and ground from the wires? I have no clue when it comes to electrical problems.

Did a search and found few suggestion checking fuse *K? I can't seem to locate from my box, anyone?

Thanks in advance
Jesse

[speednme1]

Did you remove the lights before taking the bumper off? If so, did you reconnect them when you put the bumper back on...you'd be surprise what one forgets.

[icemann427]

Firstly, purchase a light tester.

Secondly, attach the alligator clip of the light tester on a good ground and check both sides of each and every fuse located at the fuse box on the driver's side of the front bonnet, just to make sure they all work (the light of the light tester will go on if the fuses are working). I'm not sure, but the thin cardboard fuse card on the fuse box may tell you which fuse it is. If it doesn't, if you have the owner's manual, that might. If you can't figure out which fuse it is and each and every fuse is not broken and is hot on both sides, go back to the rear bumper. I'm assuming you re-plugged the wire(s) back together or you did not separate them. Make sure the wire plugs are connected, well. Once you checked the connections, turn the lights back on to see if they work.

If not, unscrew the clear plastic lens of the plate light. Turn on your parking lights and move the light bulb around with your fingers to see if you get it to work. If it doesn't work, take the bulb out and look at the filament to see if it is intact. These bulbs break very easily and maybe you just broke the ancient bulb. Turn the lights off and take out the one bulb that does work and plug it into the socket that isn't working. Turn the lights back on. If it works, you know it is a bad bulb. If it doesn't work, you know you have some sort of a connection problem.

Remove the bulb and find a good ground for the light tester back by the rear bumper. With the lights on, touch the metal positive connector of the light socket that touches the end of the bulb and see if your light tester goes on. If it does, that metal connector may just be dirty or the side grounds that ground the bulb to the system may just be dirty or are loose. Turn the lights off and scrape the connector/ground with the pointy end of the light tester to make good contact points. Retry with the bulb plugged back in. If it works, you are good to go.

If you touch the positive connector of the bad side light socket and you do not get the light tester to go on, you probably have a connection problem with the wire. You should be able to find the wires (I think they are white) inside the bumper and test them with the light tester. Hopefully, the light tester goes on when you probe them. If it/they are hot, your problem will be somewhere where the wire touches the light socket. With the lights off, remove the socket and start checking for a good wire connection. If it is connected fine, clean the socket and check to see if it is grounding around the bulb, well. Turn the lights on and see if it is hot where the wire connects to the socket with the tester. If it is hot, it will just be a matter of playing with the socket and bulb until it works. Just remember, the socket needs to be grounded for the bulb to work. If the wire(s) are not hot, you will have to work your way forward from the bumper following the wire(s) forward and continue to test it/them until you find where they are hot. Make sure the wire is not exposed somewhere (if it is, the fuse will probably be blown, though).

[T77911S]

good to see someone suggesting a test light.

looking at the diagram again it shows power going thru a fuse but it is not numbered and it is not on the panel. (on the diagram,)
power comes off the right side lights so make sure the right side parking lights work.
I would look at the power connections from the car to the rear lights. its inside the rear bumper.
especially since you had the bumper off.
trying to get those reconnected is a real pain.
I relocated the connections so I can easily remove my bumper.

[gsxrken]

My 86 had a small inline buss fuse on a wire hanging under the main fuse panel. It was labeled KKK if I'm not mistaken but verify for yourself. Whatever else it did, it also was for my license plate lights
YMMV

[cody818]

Thanks for all the replies.

Other lights are working fine, including bulbs and socket for the license plate is good. Bumper and tail light housing is moved for testing. I will need to get a tester to test the wires and fuse.

I've been looking all over the fuse box to locate anything that is labeled KKK but no luck. What does this look alike? You happened to have pic of this?

[T77911S]

i have my bumper off now. I will take a look.
i did not see any fuse for my lights but like i said, they are fed off the right side park lights so if those work the fuse at the trunk and wiring back to the rear of the car should be good

[will hung]

I had this issue. When you turn on your lights, does the parking light on that sides brake light go out? If so, then you have a break in that wire. Took a lot of continuity testing to figure that out for me.

[cody818]

So, finally got done testing all the wires, continuity is good. Ground is good but no power to both plate lights. Checked all the buss fuse and they seem okay, nothing broken. What's driving me crazy is that all the lights are working, including both brake lights. Only thing I couldn't find was the "K" fuse. Anyone have pic of where and how this fuse look alike?

[gsxrken]

You can see the black fuse holder labeled "KKK" in the below pic. The wire it's on appears to be gray. The fuse holder is disassembled.
In it, by the way, was a 2a or 3a fuse wrapped in tinfoil. Pure insanity.

[IMG]Porsche 930 fuse panel (1986) by Ken Brown, on Flickr[/IMG]

[cody818]

Remove the fuse panel this weekend to locate KKK fuse that was hidden underneath. Indeed, it was a blown fuse. Thanks everyone and thank you for a pic Ken.

Jesse