Left Front Turn Signal Issue

[snowman1510]

Hello,

 

I have been chasing down and issue with my left front turn signal. The signal will not function. All the other signals on the car work. The left rear flashes quickly. The left indicator on the dash flashes once and stays off.

 

The tungsol fuse clicks quickly. The bulb is new and functions (wiring and light for in bucket touched to batter and burned brightly). The lamp itself has been removed spade terminals sanded and bulb contacts have new solder. Where the green and white wires meet the yellow and white wires has been sanded as well as both the white and yellow spade terminals. I believe the yellow wire enters onto the fuse board at section 8 according to the shop manual.

 

I cannot locate the white wire. I know it enters a thermo circuit breaker but i don't know what it looks like. If any assistance could be made to point me towards the right area for the thermo circuit breaker i am all ears!

[Bloo]

1 hour ago, snowman1510 said:

I have been chasing down and issue with my left front turn signal. The signal will not function. All the other signals on the car work. The left rear flashes quickly.

The left front signal is disconnected from the system someehow. Usually that's because of a bad ground at the socket. The left rear flashing quickly indicates that the left front is not present.

 

1 hour ago, snowman1510 said:

The left indicator on the dash flashes once and stays off.

That's just plain weird. I'd ignore it for now. The LF dark and the LR flashing too fast will point you to the real problem. If this persists, we can troubleshoot it later.

 

1 hour ago, snowman1510 said:

The tungsol fuse clicks quickly. The bulb is new and functions (wiring and light for in bucket touched to batter and burned brightly). The lamp itself has been removed spade terminals sanded and bulb contacts have new solder. Where the green and white wires meet the yellow and white wires has been sanded as well as both the white and yellow spade terminals. I believe the yellow wire enters onto the fuse board at section 8 according to the shop manual.

I don't understand what this means. Make model and year would help, and a wiring diagram if you have it.

 

Nevertheless, making the wild assumption that these are fairly normal postwar Buick turn signals, your bulb should have 2 contacts on the bottom, and 2 filaments inside, one big and one small. There are 2 contacts in the socket. 2 wires go to the socket. One is park light (connects to small filament) the other is signal light (connects to large filament). Make sure this is all true.

 

Both filaments ground through the socket. The socket can't be hanging loose to test, it must be attached.

 

The big filament is the one we are interested in. Not sure what you meant about the yellow and white wire. Is there a wire missing? That would sure do it. If both wires are there, try adding a ground. Either solder it to the socket and run the other end to a good ground, or for a test you could hose clamp a wire to the socket and run that to a good ground.

 

If everything above checks out, and grounding the socket does not fix the problem, one of 2 things is the cause:

 

1) The wire that connects to the big filament of the bulb is broken, unplugged, corroded, squirrel-eaten, cut, or otherwise disconnected somewhere between the LF bulb socket and the turn signal switch. Follow the wire from the front of the car to the signal switch and look for damage.

 

2) Or... The signal switch is bad. Since it shares the brake light bulbs in the back with the signals... well it probably does, you didn't say what car.... the left front signal has it's own contact in the signal switch. That contact in the switch could be bad with everything else still working. In that case, there is probably a plug where the turn signal switch exits the steering column. Maybe you could check there with a test light. Test with the clip of the test light grounded, and the probe stuck in the backside of the connector, touching the brass terminal for the wire that goes to the left front. Turn left signal on. If the test light flashes fast along with the rear signal, the switch is OK. If the test light stays out, the contact in the switch is probably bad.

 

 

Edited December 15, 2023 by Bloo (see edit history)

[Frank DuVal]

Typically the left front turn signal is wired to the left dash indicator. 

 

The left rear flashing quickly is why the flasher (not a fuse) sounds quick clicks.

 

I would look for a bad ground at the lamp. Jump from the brass shell to a good chassis ground and see if it starts flashing.

 

Not having a shop manual for your car, what is it again?, I can only assume the white wire is the parking light, and goes to the headlamp switch, which contains a circuit breaker. The green and then yellow wire would be the turn signal wire. Awaiting car info and someone with a shop manual to confirm.

 

🦃 🐖  🍠  🍲 🎄 🎄  🕎 🕎 ❄️

[Bloo]

29 minutes ago, Frank DuVal said:

Typically the left front turn signal is wired to the left dash indicator. 

Oh man are you in for a surprise... I mean, taking the industry as a whole you are not wrong, and that method just works as expected, but we are faced with the possibility that this might be a 50s Buick.   GM did some things back then that cannot easily be explained. Maybe the engineer had been wandering in the woods around Seattle during the Mad Season, or just returned from a Vision Quest somewhere in the deserts of the Southwest.

[EmTee]

What I can make out of the picture on his profile looks like a '55 Buick...

 

 

[Frank DuVal]

Well, yes, there are many iterations of turn signal wiring. Get into the amber rear lights, third brake lights, etc, yikes! But, one can usually say the front turn signal lamp is not wired directly to the rear turn signal lamp on a Buick with factory turn signals, when the rear lamps function as both brake and turn, because of they were wired together the front lamps would light when one stepped on the brake! It is the turn signal switch's job to connect them at the right time.😉

 

Snowman, what year Buick? I see no profile picture.  ☃️

 

🦃 🐖  🍠  🍲 🎄 🎄  🕎 🕎 ❄️

 

 

[snowman1510]

Hello! Sorry I forgot to add it is a 1955 Buick Super. I am at work currently and can add more to the discussion this evening. Thank you!

[snowman1510]

Connections at terminal and and example of the light.

[Barney Eaton]

Looks like the entire connector could use some TLC

The white wire is missing the screw and the orange terminal is barely connected. 

I would take the connector off and clean it up on the bench,   also clean up the ground wire 

connection

[snowman1510]

Yes, I had the screw and plate off for this photo. They are connected currently.

[Frank DuVal]

There is NO ground wire! I hardly ever see a ground wire on a lamp assembly of this period. The ground is by mechanical contact of those screws/nuts , and after almost 70 years these connections are suspect!

 

Also, on early and FC Corvairs we have a lot of issues with the brass shell that holds the lamp, covered in black in your photo, not having a good ground to the assembly that is bolted to the car. The good solution, but not if worried about AACA or other stock judging, is to remove that cover on the shell enough to solder a wire directly to it, then attach the wire to a clean chassis screw.

 

I did mention the test for a good ground, remove the lens with the assembly bolted in place, and touch a wire from a good ground to the brass shell of the lamp. If this makes it work, poor ground is the issue.😉

 

🦃☃️🕎🎄🎄🍲🍠🐖

 

Edited December 15, 2023 by Frank DuVal (see edit history)

[snowman1510]

Okay, so I cut the boot back to expose the shell of the unit. Placed a tester light with a good ground on it and touched the shell. The tester was flashing at a rapid rate just like the rear turn signal. The bulb does give off a very faint glow, but nothing substantial enough to see. Thank you Frank for the step by step process. You suggested soldering a new line to the brass shell and screwing that to an area of good ground as an option. As a second option how would I repair the original ground? Thank you!

Edited December 15, 2023 by snowman1510 (see edit history)

[Bloo]

The shell should be grounded. It isn't. You just found the problem. 👍

 

The flash proves the switch and the wire are OK. The shell, if grounded, would have no voltage. Since you are getting voltage between the shell and ground, that proves beyond any doubt the shell is not grounded.

 

Edited December 15, 2023 by Bloo (see edit history)

[snowman1510]

Hi Bloo, I was just reading your earlier response right as you posted. To ground out the shell should I solder a new lead, or just replace entirely. The bucket it is in is heavily corroded (maybe the issue). Below is an attached photo.

[snowman1510]

I did clean the lock washers ', bolt, and screw holes where the bucket attaches to the fender previously for grounding. I suppose the Rusty bucket is my issue?

[buickbrothers]

Agree that checking the ground is the first step. I've been putting my 55 Roadmaster back together which included installing the dash, steering column, all the wire harness connections under the dash and throughout the frontend including head lights and turn signals. etc. Since I don't have the fenders installed, I had to ground the turn signal housings to test them. Also had to ensure all the lights in the speedometer (turn signals gauges and high beam indicator) were also grounded. The single blink of the turn signal is indicating it's not grounded. Mine did the same thing until all grounds were solid.   

[snowman1510]

Would soldering a new line to a ground be the correct fix or new bucket?

[Bloo]

I'd just solder a wire on it and run it to a good ground. The closer to the socket shell the better, like on the outside of the socket shell itself if you can. It is hard to tell from the pic if that's possible, but the closer you can get to the bulb socket the better. Anyplace where the metal is stamped/crimped together can get resistive. If you can solder to the outside of the socket shell you have eliminated all of those places.

 

 

 

[snowman1510]

What gauge wire do you reckon I should use? Thanks again!

[Ben Bruce aka First Born]

27 minutes ago, snowman1510 said:

What gauge wire do you reckon I should use? Thanks again!

I would use 12ga.

 

  Ben

[Frank DuVal]

It's a 21 C.P. bulb on 12 volts. Even when the turnsignal filament and the parking lamp filament is on at the same time it won't pull more than 3 amps. 18 to 16 awg would be fine. Yes, soldering the wire to the brass socket is best. Bypasses the brass shell to the housing crimp.

 

If you have access to a sand or soda blaster that might clean up that lamp housing. Then paint the reflective area with gloss white paint.👍

 

🦃🕎🍲☃️🍠🐖🎄🎄❄️

 

Edited December 16, 2023 by Frank DuVal (see edit history)

[snowman1510]

Thank you some much everyone for your help!!!

[Beemon]

Attaching a new ground wire probably won't fix the issue if it hasn't been fixed by now. The bulb grounds to the socket housing. You are going to need a good bit of scotch Brite or even medium grit sandpaper to polish the socket housing back to bare metal. Then the fit might be off with the made in China bulbs, so you might need to shim or oblong for good contact. Install with dielectric grease to keep from rusting again. 

 

Just did this on my 56.

[EmTee]

Sometimes with an old (or cheap new) socket if the bulb fits too loosely I will add a little more solder to the contacts on the bulb so the bulb fit tighter in the socket.  This can also help if the contact springs in the socket are weak.

[Frank DuVal]

23 hours ago, Beemon said:

Attaching a new ground wire probably won't fix the issue if it hasn't been fixed by now. The bulb grounds to the socket housing.

Yes, but.... the socket then grounds through the socket to lens housing crimp which grounds to the body through the mounting screws. Many people forget the socket is a different stamping than the lens housing stamping or casting. This is why soldering a wire to the socket works well, it bypasses the socket to lens housing connection.

 

I run into this all the time on the brass socket to aluminum housing crimps. A test for a bad crimp is to use a screwdriver tip to touch both the socket and housing at the same time. The Buick housing in the picture does not look like aluminum, but there are still two parts there.