rear lights on longhood

[Johan123m]

My rear lights and sidelights aren't working anymore..

front lights and turn signal lights front and back are fine...

didn 't check stop lights or reverse lights yet

I checked everything i could think off: wiring back to front, wiring unther dash, grounding, bulbs, fuses, all connections (even inside the housing)

q for the specialists: where could be the problem? I'm lost!

Ps. it's a '73 T

Thanks for your advice!

Johan

[red67]

i'm probably wrong, but i had a similar problem with both my rear lights.
after finding all the wiring diagrams and checking fuses and tracing that everything was connected and fine as a last resort i cleaned up the earth connections with emery paper (really light grain sand paper) so they had a better contact and it sorted it out. i found that an earth on one light can knock out several. as i said i'm probably wrong with your case, i'm an amateur. but someone else will have more knowledge and experience.

[RWebb]

what is the last place where you have +12 VDC when using the normal ground that the lights use on each side?

[vntgspd]

Paul is right. There is a ground wire that goes to the frame rail in the rear fenderwell just forward of the light assembly. This is in a spot that is prone to water and road dirt and may very well be corroded. That's the first thing I would check.

Good Luck!

[Johan123m]

I only did a visual check of everything, but I didn't know there was a ground wire on the frame rail, so that should be it!

My car was painted a month ago and the rear lights were disconnected. The wires were left in place, but I probably pulled a bit to hard on them wenn I reinstalled the lights.

I'll be checking this evening and let you know! If it's correct I'm gonna buy you guys a few beers

[Johan123m]

Nope...it's not it....


I was really sure that this would solve the problem, but I cleaned the groundwires on both sides and the problem remains...

Backlights and sidelights front&back aren't working. Turn signals-lights, stoplights and high&low beam work fine

Are the sidelights and backlights the same circuit? In the back they are, they're even connected with eachother. Are there other groundwires on this circuit?

Were could be the problem...any suggestions?
(checked the fuses and bulbs and did a visual check of the cables inside the lighthousings and lightswitch-cables unther the dash)

What now....

[vntgspd]

Did you check to see that 12v are coming out of the dash switch when you pull it out to the first position? I'm not sure if the wires exit this switch to the fuse block then go front and back as necessary, but yes, front and rear marker lights are on the same "switch".

[ossiblue]

You haven't said if you've checked for voltage. I'd suggest you start there with a volt/amp meter or even a test light. Work your way back from the rear light. I discovered a bad fuse once that looked good but had a hairline break that was the cause of light failure just like you describe.

[red67]

i knew i shouldnt have been a smartass and attempted to offer advice to others as coincidentally my brake and rear lights have just gone down after 6 months of being ok now!
i'm gonna follow the advice to johan above. johan how did you get on? did you sort yours?

ps with regards to fuses is it advisable to replace them periodically? and if so are they available in any car store or do we need special suppliers like pelican.

many thanks
ps above in on a 1967 911 2.0

[Johan123m]

Hello Paul,

Sorry to hear that you're in the same boat...

I wasn' t able to solve the problem yet. Before ripping everything apart again, I changed all the fuses (for a '73 they are widely available in any carshop-i guess they're the same for a '67?), but it made no difference.

Now I'm gonna clean the groundwires on the front turnsignals (because the sidelights are also connected to the rearlights).

I've traced the whole route down on a blueprint and could see that after the fuses (fusebox 2- nr. 5&6) and after the lightswitch the wire goes to the turnsignalswitch (probably for low&high beam) and then one wire leaves to the ignitionswitch. I'm gonna check those to.

If none of the above works, I start mesuring from the rear to the front to find 12v (like some people suggested)

See ya
Johan

[Mo_Gearhead]

Pull all of the 'lamps' and use emory cloth (1000 or 1500 grit) on all of the lamp tips/ends and sides and the metal strips and 'barrels' where they make contact.

Over time these connections can corrode and build up resistance.
Polish them until the metal is clean/shiny!

[jeff1hughes]

try to clean the contacts in the fuse box. In my '71 sometimes just playing with a fuse would change the electrical flow so things worked.

[Early_S_Man]

NEVER, NEVER use any form of sandpaper or emery cloth on factory 911 chassis panel connectors, or you will remove the silver plating and expose bare brass underneath ... causing serious corrosion problems in the future!!!

[Mo_Gearhead]

Early,
Well, that may be good advice if your connectors are in good condition, however in restoring my 38 year old car, I could get 12 volts everywhere but some of my lamps would not function.

The lamps, sockets and lamp bodies were dirty, corroded, etc. and would NOT complete the circuit. Used emory cloth to clean them ALL, now EVERY lamp works.

Granted, I may have to clean them again at some point in the future, but what was my alternative?

[Johan123m]

Still haven't solved this issue!

Cleaned the groundwires on in the front - changed fuses and checked if the panel connectors were clean...all ok!

I noticed that something is draining my battery(2 days and the car won't start anymore!) Does this knowledge narrows the search down?

[rlh930]

Johan123m,

Several folks have suggested that you get a voltmeter and try to troubleshoot the problem in a systematic manner by checking voltages. You don't seem interested in this advice. My guess is you won't make much progress until you do this.

[kplackmeyer]

For basic troubleshooting, you really do need to find out if you have voltage to the socket and ground to the socket. Otherwise you are chasing ghosts. Get a test light, open the deck lid, and connect the alligator clip to a metal part of the motor. Remove the lens and bulb. Touch the probe to the small tab at the back and see if the light goes on in the test light. If it does, move the alligator clip to a +12v source in the engine compartment (there are several under the fuse panel cover on the left side). Make sure you have +12v by touching the motor. It should light. Now touch the sleeve of the light socket.

Oh..and be sure to turn on the lights before you test.

--If you get no light in the first test, you have a voltage problem.
--If you get no light in the second test, it's a ground problem.

[Johan123m]

Thanks Kerry,

That's some usefull and well explained advice. I have to admit I know nothing of electrical issues....
I've a test light but I barely know how to use it. Also I don't know where to check. So, it really is not a question of not wanting to follow advice but more a question of not knowing HOW...


Johan

[RWebb]

test light is ok - starting from the battery where have you checked?

[Dantilla]

On my '73, I finally gave up on the tail light housing itself. I had one from the '87 Parts car. I swapped it, and now everything works fine.