1959 Cadillac Turn Signal and Brake light Issue

[Coupe Deville]

Hello-
          My 1959 Cadillac has had a turn signal problem for quite some time. The left and right turn signals in the front work fine. The rear lights are the trouble. when you put the left turn signal on the rear light does nothing. But when you put the right on both sides left and right flash. I changed out the turn signal flasher under the dash it didn't help. Now just recently the turn signal fuse keeps blowing out and the brake lights don't work now either. I think it might be the turn signal switch. I'm not very concerned about the turn signals right now, but I do need the brake lights working as soon as possible. Thank you   

[J. Gomez]

Gavin,

If you do not have the wiring diagram you can download a copy from either of these two sites;

http://www.auto-wiring-diagram.com/wp-content/uploads/2012/05/wiring-diagram-for-1959-cadillac-all-series-part-1.jpg
http://www.auto-wiring-diagram.com/wp-content/uploads/2012/05/wiring-diagram-for-1959-cadillac-all-series-part-2.jpg

or

http://www.oldcarmanualproject.com/tOCMP/wiring/5765wiring%20diagrams/cadillacindex.htm

For the symptoms you are describing it sounds like the directional signal switch is the problem, a defective turn signal switch would cause all kinds of havocs.

The issues with the signal switch when is place at the center this makes a connection from the brake light wire “natural” to the rear left and right side (pink and violet wires) lights.

When you place the directional switch to either left or right the contacts switches the side it is set for the flasher to operate leaving the opposite side for the brake only.


If there are no shorts on the pink or violet wires going to the rear lights, you could temporarily disconnect the connector under the steering column (from the turn signal switch) and connect the natural (from the brake light switch) to both pink and violet at the main hardness connector. This would give you the brake light back.

Good luck..!

[Coupe Deville]

Would i need to put the turn signal fuse back in? Or does the bake lights not run thru the fuse box?

[J. Gomez]

Would i need to put the turn signal fuse back in? Or does the bake lights not run thru the fuse box?

Both circuits are feed by the same fuse, so yes you will need to reinsert the turn signal/brake light fuse.

[Big Fins]

The T/S switch on these cars are made of spring steel and are almost indestructible as far as the switch itself goes. So it's going to have to be a wiring issue.

[J. Gomez]

The physical switch would be made of plastic with the sliding lever most likely of Bakelite type material. The tension brass contact strips are inserted on both sides inside the plastic case while the slider provides the switching.

Wiring issues such a short on the front or rear path or an overload may have cause the plastic to melt around the brass strips that could add to more problems. Although uncommon it is a possibility.

Once the turn signal switch is disconnected from the main hardness plug the path for the rear lights (pink and violet wires) would need to be tested before performing any temp connections.

[cadillacmike68]

The fact that both light up with the lever in one direction means wires in contact with each other somewhere along the line. It could be up front at the switch or anywhere back to where the right and left separate somewhere under or behind the trunk.

[INTMD8]

You guys have any thoughts to maybe a bad grounding at the rear of the car ?
Maybe the hot wires are good , but the grounds are bad. Just a thought.
Roy

That was my first thought.    My 59 is doing the exact same thing as Gavin's car but I have not yet investigated.

When I get it figured out I will report back.

[59-in-pieces]

Here are photos that may help the discussion.
As someone said the turn signal (T/S) is steel - and bullet proof - and that is correct on the top side under the horn ring inside the T/S collar, but that is only the mechanical part and unlikely the problem - see photo
The underside of the T/S mechanics is where the actual electric switch is located - where the real work is done for brakes and signaling - see photo.
Note that the switch itself is "plastic" with contacts and ball bearings for connections and has wires that have their insulation fused as like a strap and then wrapped with tape to avoid chaffing in the steering column - see photo.
Check that area out for chaffing/abrasions - tape if needs be and retest.
I agree with Roy and others that the problem is a break in a wire, or 2, that is causing a faulty ground.
The wires leading from the steering column for brake, back-up, license plate, and T/S lights run along the driver's threshold area and back to the raised area of the trunk back and split for the R & L tail fin sides.
I would run continuity tests from the T/S switch leads to the harness connector at the split.  If all ring out then directly back to the tail light harness connectors or bulb sockets of the tail lights.  If continuity is lost in any one of the wires (T/S to split harness connector, harness connector to tail light connectors) there is a break in that wire - trace it back and properly splice.  If however all wires ring out - which is unlikely, the problem is more likely the switch - which I have had to replace in only 1 car.
Have fun,
Steve B.

[Coupe Deville]

Hello everyone, I tested the leads coming from the turn signal switch they both worked fine and independently. I bypassed the turn signal lights anyway just to get the brake lights working but it's still blowing the fuse. Would a grounding issue cause a fuse to blow? I just noticed the housings were the lights sit there is a single pre drilled hole for each light. I put screws in these holes thinking it would give it a better ground. Things went down hill from there. That's when I started blowing fuses. And if there would be a short where most likely would it be? I tore the interior out and traced the wires and found no shorts. Thanks Everyone

[59-in-pieces]

Gavin,
Did you run a continuity test on each wire as described above between harness connectors all the way back to each of the tail lights.
The 59 is a tricky beast.  Wires can be broken within their insulation, so the breaks are invisible, particularly when the harnesses are wrapped in old style friction tape.
Can you shoot some pics of the holes you are talking about in the lights and the harnesses you are tracing.
I don't understand your 2 wire description and how you bypassed turn signal function for a brake function which uses a different switch at the brake pedal.
Just for giggles - look behind the driver's side kick panel at the multiple wire harnesses that go through the door jam as there are several spliced wires in that area and check to see if those wires are broken - very notorious place for broken wires and multiple power source splicing.
I love a mystery.
If you want to take this off-line, PM me.
Have fun.
Steve B.

[Coupe Deville]

Hello again, I tested the wires coming down from the switch they both flashed independently. I would test the power coming out of the actual light sockets but the turn signal fuse keeps blowing. I have below the pictures of how i thought i was supposed to bypass the turn signals just to get the brake lights working. The fuse constantly blowing is confusing me. I am also putting in a picture of the left inside tail fin of the rear light wires. It looks like someones been here before me. The third picture is of the pre drilled holes i noticed in the bottom of the tail light housings. I could worry about the turn signals later if it wont be a easy fix but i do need the brake lights working as soon as possible. Thank you everyone!

[Big Fins]

Those screws that you installed are just anchor screws for the light pods so they won't twist and fall out. I wonder if the screws that you used are too long and are pinching some wiring in the holder assembly itself. The originals were only 1/2" long.

[59-in-pieces]

Gavin,
Roy is right, you need to sort out the wires in the various harnesses.
Earlier it was suggested that you look at some wiring diagrams - good advice.
But, for my eyes they are too hard to read.
Since I have done these cars many times, I would suggest you acquire a wiring diagram that shows the wires in their original colors - very easy that way to trace.
Here is the guy I got my 59 diagram from several years ago and recently for my 47 convrt, and they come laminated in plastic - easy to clean.  Go for the approx. 18" X 26" size
www.classiccarwiring.com - 917-861-9131. 
Have fun,
Steve B.

[Coupe Deville]

Hello Everyone, I ran a long wire from the brake light switch directly to the rear were the wires hit the tail lights. I spliced the wires to the left lights only (right lights not connected). With a little fiddling i got them working. So now the left is working properly. When i get back to the garrage i will reconnect the right light wires and go from their. I will be gone this weekend and be back Monday. When i get back i will let you guys know what i found out. Thanks everyone. Have a nice weekend.

[Coupe Deville]

Hello everyone sorry for abandoning this post for awhile. I sorta got it going.
The right rear tail lights, stop light and turn signal all work. The problem is with the left
Rear now. The running lights work. The brake light doesn't work. The the turn signal works. The natural wire has power, the violet wire has power for the right brake light, and the left has no power from the wires from the turn signal switch on the steering colum. When you put on left turn signal the wire has power but no power from the wire for brake light? Sounds like the turn signal switch to me. Any input? I hope it's not the switch thou. Thanks!

[J. Gomez]

Gavin,

There were two styles of turn signal switches the Delco-Remy and the Boyne. The Delco is/was a more robust type with the slider brass contacts inside a Bakelite case than the Boyne with the brass strips inside a plastic case in handling heavy loads and heat.

You may need to identify which style you have in your car. If yours is a Boyne the plastic channels that holds the brass strips may be melted you may be able to get it fix, it all depends.

When you turn the directional switch for the left side, the yellow (flasher 12V) is switched onto both pink and dark blue. The natural from the brake light switch is extended just to the purple for the right side brake light.

If your left side is out, I would have to say the problem would be most likely in the directional switch. 

Good luck..!

[Coupe Deville]

It's strange. Sometimes the left turns signal works sometimes not. Same goes for the brake light.
When I wiggle the turn signal lever it woks sometimes.

[J. Gomez]

It's strange. Sometimes the left turns signal works sometimes not. Same goes for the brake light.
When I wiggle the turn signal lever it woks sometimes.

Possible a bad or lose connections inside the switch or wire connection. It looks like you have to take the switch out. 

[Coupe Deville]

Ok. So just pull the steering wheel. Is there anything to look out for or things that might fall out when I remove the steering wheel and switch?  Any tips on removing the switch will be appreciated. I know to be very carful with the horn ring. We already broke it once and it didn't come cheap.