Brake Light question

[roodog911]

Had a full body respray done on my '84 Targa last winter ... haven't had much chance to drive it until recently.
A friend told me my left brake light wasn't working ... no biggy right?
Checked the bulb, it was good, a little gentle prying on the contacts and a gentle squeeze on the socket to assure a good contact. No improvement.
Noticed last night when pulling into my garage that the left front driving light came on when the brakes are applied.
Not being lazy, COPD limits my abilities to crawl around under the car ...
Anyone experienced this before? Any ideas what I should check next? Wiring issues?
Thoughts and comments would be appreciated ...

Willie

[DRACO A5OG]

Check the wiring are in the correct slots on the fuse box using the bentley guide

[roodog911]

Thanks Draco, great suggestion, it appears that the wiring at the fuse panel is correct according to both Bentley and the descriptions embossed on the inside of the panel cover.

Need to quit for tonight, will start again in the morning.

[javadog]

I would start by pulling the left rear light and checking that the wiring there is attached to the correct terminals.

You may also have to do the same thing in the front, but start at the rear lights.

JR

[DRACO A5OG]

That's right, you did say you did some re-spraying. If the shop removed the marker assemblies, then they may have not reconnected properly, especially the ground.

[brighton911]

Second on Draco's comment on the ground. The driving light is most likely coming on because the brake light has poor/no ground so it's getting some ground where ever it can.

[bell]

Had this problem before. ....
The engine lid light shares the circuit with the left parking lights. ... if the lid light is plugged in backwards it can cause a direct short. ..... May be worth checking out...... even though it's on the parking light cirquit. ..

[roodog911]

Thanks for the additional suggestions ... I'm off to the garage to see what might work.

A question regarding a possible ground issue. All the lights (tail, brake, back up, directional) are in factory closed shell which is the back of the tail light assembly. The wiring runs through a single hole in the back and connects to the wiring harness with a single plug. With all other lights functioning, am I wrong in assuming that a ground is acheived by the contact of the metal TL assembly with the body?

Willie

[roodog911]

Thank you Draco, javadog, brighton911 and bell .
I checked each of the suggestions and couldn't identify any particular issue, however several connections and contacts are now cleaner than before.

My neighbor stopped by late in the afternoon to see what I had been up to. Finally a second set of eyes to view the light as I stepped on the peddle rather than watching for a reflected glow on the wall.

Seems as though the light would work intermitantly ... I guess my initial gentle squeezing of the socket was too gentle and the bulb still had a bit of wiggle room.
Rather than pull the assembly out again and remove the back panel a second time I experimented by wrapping the shank of the bulb with a single wrap of electrical tape and trimmed the tape to leave about an 1/8 of an inch strip just below the glass bulb.

The light shines bright and steady and the wiggle is gone. Hopefuly the heat of the bulb will not affect it.

Flame suit is on ... fire away ...

Willie

[bugstrider]

Willie,

Thanks for the write-up. I just discovered I also have a strange bulb issue.... I have a 78 911 SC that when the running lights are pulled, everything is on. However, when I apply the brake peddle, the driver's side brake comes on stron while the passenger side goes completely out. I have no idea why, so my quest continues.

[DRACO A5OG]

You could also buy some Rubber Orings at Harbor Freight and place them on the blub then push them down against the socket so they do not "wiggle" around.

[DRACO A5OG]

Originally Posted by bugstrider

Willie,

Thanks for the write-up. I just discovered I also have a strange bulb issue.... I have a 78 911 SC that when the running lights are pulled, everything is on. However, when I apply the brake peddle, the driver's side brake comes on stron while the passenger side goes completely out. I have no idea why, so my quest continues.

Check with a Volt Meter to make certain you are getting voltage there, if not, it is most likely than not a ground issue. 1st check the ground, it sit on the chassis behind the the tail light assembly, clean and make tight. That area is a very harsh environment, you will know what I mean when you open it up.

If that does not do the trick next would be is to open open up the light assembly and check for fractured PCB board type panels behind the sockets and also verify brown ground wires is attached.

[bugstrider]

Thanks Draco,

Will do that today. Also a good motivator to get that third brake light installed too.

[The cap'n]

Make sure you have the correct bulb in each socket. Double filament in the brake/tail light socket, single filament bulbs in all the others.

The Cap'n

[bugstrider]

Ok,

Had some extra time to dive into my odd tail light dealio. Pulled the light housings, OMG! There was 35 years of crap/dirt/rocks/oil/ you name it... Pulled the back housing cover too......yuk!


Cleaned things up and found out that the running/stop plug was loose. Adjusted the brass tabs and re-bent the pot metal tabs to snug up the plug plate to the metal housing. (Mongo alert) this idea worked on the drivers side, however I guess overconfidence lead to too much pressure on the passenger side because I broke off both tabs(curses!!!!!!!) I am hoping that JB Weld a metal band and more JB weld will fix this boneheaded mistake.







Fresh blob of JB weld along with another section of metal strap at 90 degrees. If the pressure of the insertion of a simple bulb breaks it off, then it stays broken and I guess the search for a tail light housing begins.....




While the repair is curing, I reinstalled the non-F-ed up side, replaced the crusty seal, and new bulbs.



Discovered a good substitute for the aged out gooey putty/sealer that went on the rear plate of the light housing





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[DRACO A5OG]

Make sure you check the grounds to the chassis, if I recall correctly it is on the passenger side tail light assembly mount.

[bugstrider]

Roj Draco,

Will be sure to do that when I put it back together. Got everything to work properly as long as I had ample pressure on the bulbs. Indicating just a light connection on the bulb. Combine that with road vibration and ya got intermittent lights.


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[DRACO A5OG]

OP sorry for the hi-jack

[bugstrider]

Very true.... Sorry


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[HarryD]

Had similar problems. Tried the JB Weld fix. Lasted about 6 months.

Went to my FLAPS and bought a universal socket for a two filament bulb. Used my dremel to enlarge the hole slightly and pressed the socket into place. Hooked up the wires and no more problems. Cost? About $2.00 and a few hours.