Stop light & directional signal dilemma

[straight8pontiac]

Good morning all... The car in question is a 1953 Pontiac Catalina. I am having intermittent stop light and directional (turn signal) issues where one or the other will not work or sometimes neither will work. It has now become a hazard to drive and tour with our friends.

 

It is my understanding that the stop light circuitry goes through the directional switch that is in the steering column. If this directional switch is failing, can it be repaired or does it have to be replaced? If replacing, is this a year and car specific piece?

 

Thank you for any help that you can give... Dave

 

 

[OrtonvilleBob]

The switch itself is year specific, 1953-1954. Replacements are sold online for '53-'54 Chevrolet. The Chevrolet switch is identical to the Pontiac version except for the attached wiring harness. I replaced the turn signal switch in my '53 Pontiac with the Chevrolet replacement. The only issue was forcing the wiring harness to route in the correct direction (Chevy wires route clockwise within the steering wheel hub, Pontiac routes counterclockwise).

 

However, even with a brand new switch there's a high probability you will still have the same intermittent brake light/turn signal problem if the cancelling mechanism is worn like it was in mine. If there's slop in the turn signal lever, i.e., the lever doesn't return to a tight center position after making a turn, the switch contacts will be left in an indeterminate position (not quite turn signal mode, not quite brake light mode). When you remove the steering wheel you'll be able to see that years of wear has made the cancelling mechanism sloppy. By trial and error I was able to fabricate some shims to tighten mine up.

 

If I had to do it over I would have taken the existing switch apart and cleaned the contacts rather than replacing it. I took my old one apart out of curiosity. These photos should help if you decide to replace your switch or clean it as a first step.

 

[straight8pontiac]

OrtonvilleBob...thank you so much for your perspective and those photos. Very interesting to see what the guts look like as I have not taken the steering wheel off yet. From photo 1 to photo 2, is it the one screw at the lever which holds that top section?

 

In photo 2, am I correct in assuming the 2 phillips head screws hold the next part together allowing me to get to the contacts?

 

California Parts Restoration offers a turn signal replacement which looks like the contacts only... not sure, would have to call and ask.

 

Thank you again for your help... Dave

[OrtonvilleBob]

Dave, yes, you are correct about which screw(s) get removed to advance from one photo to the next. By the way, I found the greatest amount of wear under that one screw that holds the lever in place. It's a shouldered screw and the metal directly below it (the cancelling mechanism) was worn. That contributes to the mechanism not positively indexing to the off position. Also, in photo 2 you see a vertical bar just to the right of that screw location. It's actually spring steel and helps force the cancelling mechanism into the off position. I found it to be loose and that's a location I added a shim.

 

If you buy the replacement switch from CPR it's C5942764RP. It's actually the Chevrolet reproduction switch and does have the harness attached. As I previously mentioned, the harness will not fit our Pontiacs without minor rework (bending the wires so they route in the opposite direction and swapping your old harness clip onto the new one). Several suppliers sell the '53-'54 Chevy turn signal switch so you might want to shop for best price.

 

Also, here's a wiring diagram that shows the colors of the wires in the harness that come with the replacement switch.

[straight8pontiac]

Bob, thanks so much for the added info. I will try to clean all the contacts first and based on the results I may or may not get a replacement switch.

 

Your pictures helped put me at ease in trying to understand and repair this problem... Dave

 

 

[straight8pontiac]

 

Bob... pulled the steering wheel and did have some wear as you indicated. Removed the cancelling mechanism, removed the 2 screws holding switch and found a lot of resistance in trying to pull the wires out. They did not come out as far as yours in picture #3. I don't have a new switch yet so I was afraid to pull too hard and create a larger problem for myself. Did yours come out easy to that point?

 

I did break one solder joint but I believe I was able to re-solder. How far down into the steering column do those wires go? I did put the units back together.

 

Present condition--- when pulling the light switch out, I have parking lights in the front but no taillights. Pulling the switch all the way out, I have headlights and no taillights. With the car running, I only have signal lights in the front. This suggests to me that I am not getting power through the wires going to the rear lamps for any lights.

 

I have brake lights because I ran a dedicated wire for power and a dedicated wire to the stop light bulbs.

 

If I put the original power wire on the brake light switch, I have nothing at all at the rear lights.

 

Maybe it is not the turn signal switch but a serious power wire problem??

 

Thanks for any suggestions on where to start diagnosing and where/what to correct.

Edited November 4 by straight8pontiac (see edit history)

[OrtonvilleBob]

Dave, those wires are indeed extremely tight. They route inside the steering column and come out at the bottom edge of the instrument panel. When I replaced my switch, pulling out those wires was probably the most difficult step of the process. Regarding the length of wires shown in photo 3, just to clarify, you unfastened the harness clip? 

 

Park lights and tail lights are powered and fused separately. The tail light fuse is the 14 amp fuse located under hood on the firewall. That fuse also powers the dash lights, the license light and ignition switch light. Therefore, I assume none of those lights works either? Not having tail lights has nothing to do with the turn signal switch or it's wiring.

 

You did or did not have brake lights before you started troubleshooting the turn signals? In other words, were your brake lights simply intermittent or were they totally inoperative? Look at the wiring diagram I provided. You can see that the feed from the brake light switch does not go to the rear of the vehicle without first going through the turn signal switch. The switch determines if the brake light feed then goes to both rear bulbs, just the left one or just the right one depending on switch position. Brake lights can not work without the turn signal switch being functional. 

 

Step 1): Is the Park Lamp fuse blown?

Step 2): Do the courtesy/dome lights and trunk light work? They are powered by the same fuse used for the brakes lights (that's the other under hood fuse on the firewall).

Step 3): I assume you have a multimeter for troubleshooting or at least a test light, right? You can verify the problem with brake lights and rear turn signals is indeed the fault of the turn signal switch by probing the three upper terminals of the turn signal switch.

Step 4): Again, look at the wiring diagram I provided. The center terminal comes from the brake switch. Press on the brake pedal and that terminal should become hot. If it does everything up to the turn signal is good.

Step 5): Temporarily jumper the center terminal to one the terminals next to it. Press on the brake pedal and one of the rear brake lights will light. Repeat for the other terminal next to the center terminal and the other rear brake light will light. If those checks pass then you know all wiring and power is fine and the problem is the turn signal switch.

 

Let me know what you find.

Bob

 

[straight8pontiac]

Good morning Bob...

18 minutes ago, OrtonvilleBob said:

you unfastened the harness clip?    No I did not, will do the next time.

21 minutes ago, OrtonvilleBob said:

You did or did not have brake lights before you started troubleshooting the turn signals?

 

Had brake lights intermittently and had to make sure turn signal lever was centered. If not, no brake lights.

26 minutes ago, OrtonvilleBob said:

You can see that the feed from the brake light switch does not go to the rear of the vehicle without first going through the turn signal switch. The switch determines if the brake light feed then goes to both rear bulbs, just the left one or just the right one depending on switch position.

For some reason and I don't know why, there appears to be no power on the power side of the brake light switch because when I press the brake pedal... no brake lights. Disconnecting the original wire to the brake light switch and then running a new dedicated wire for power, the brake lights will work. I know this is not right because I have bypassed the turn signal switch.

 

 

The car has not been put away for the winter yet, that is coming very shortly. Then I will have more time to conduct the tests you mention. With your help here, somehow I will get this straightened out. Will keep you posted and thanks for answering my questions... Dave

[OrtonvilleBob]

Dave,

   "Had brake lights intermittently and had to make sure turn signal lever was centered. If not, no brake lights."

That statement pretty much confirms the root cause of the problem: slop in the cancelling mechanism is preventing the turn signal switch from rotating back to precisely the center off position. If the cancelling mechanism is worn, the turn signal switch could be positioned part way between brake light mode and turn signal mode. Sounds to me like you've had a mechanical problem from the get-go, not an electrical problem. That's not to say the switch wouldn't benefit from a cleaning, but even installing a new switch runs the risk of continued intermittent brake light operation if the cancelling mechanism doesn't positively rotate the switch to the off position.

 

Rebuilding the cancelling mechanism is a challenge. I almost gave up with mine. Note, Summit Racing sells the entire turn signal bucket assembly for the '53-'54 Chevrolet. It includes the entire cancelling mechanism as well as the switch. I have no idea whether it can be used on a Pontiac. It wasn't available when I rebuilt my '53 Pontiac otherwise I would have bought one to see if I could swap parts. If you're curious, the part number for the Chevy assembly from Summit Racing is SUM-RP22508.

[straight8pontiac]

2 hours ago, OrtonvilleBob said:

slop in the cancelling mechanism is preventing the turn signal switch from rotating back to precisely the center off position. If the cancelling mechanism is worn, the turn signal switch could be positioned part way between brake light mode and turn signal mode.

 

2 hours ago, OrtonvilleBob said:

but even installing a new switch runs the risk of continued intermittent brake light operation if the cancelling mechanism doesn't positively rotate the switch to the off position.

If I can feel that the cancelling mechanism hasn't come back to center, I can at least manually move the lever back to center so that I am not in between the two modes. Isn't that correct? I will look at the Chevy bucket assembly.  Thanks... Dave

[straight8pontiac]

Bob and all...

On 11/5/2024 at 8:39 AM, OrtonvilleBob said:

The tail light fuse is the 14 amp fuse located under hood on the firewall

I was able to open the fuse holder and did find the fuse had blown. Got the proper size fuse, insert new one, and now am feeling good at this point. Pull the headlight switch out to the first position for park and tail lights. Look at the front of the car...park lights on. Move to the back and my happiness turned to sh.t. No tail lights! Does this mean a bad or broken wire to the back or what else? Appreciate everyone's help...Dave

[straight8pontiac]

27 minutes ago, TerryB said:

Did the fuse blow again?

Terry...just checked the fuse after your question. Removing the fuse holder from its clamp, removing the fuse itself, and then hooking it back together...taillights came ON!

[straight8pontiac]

UPDATE... I purchased a new turn signal switch from California Pontiac Restoration and started the process of removing the old switch and wires from the steering column. The new switch has the 6 wires attached but not of the same color coding. I made notes as to each wires position and its new color coding. I cut these six wires from under the dash board and l pulled the old switch and wires from the steering column. I now fed my new harness through the steering column to the under dash position.

 

To those wires which I cut under the dash, I attached spade connectors to match the new switch's spade ends. I then connected each wire to its matching end. If you remember, I did some changing of wires hoping to find an earlier solution which proved fruitless. I now went back to all of the original wiring from the brake light switch at the master cylinder to the rear of the car.

 

With the motor running and activating the left and right turn signals, each worked properly as designed. Success for the turn signals. Stepping on the brake pedal, however, did not give me any stop lights. Since the stop lights go through the turn signal switch(it's wired correctly for signals), what has happened? Why no brake lights?

 

As from our previous conversations any help is greatly appreciated... Dave

[Bloo]

Power comes from some source, probably a fuse, to the brake light switch. A wire from the other terminal of the brake light switch feeds power to the turn signal switch.

 

I don't know if the key needs to be on. Probably not but maybe.

 

1) One terminal of the brake light switch should be 6v. If not, fix that.

2) When you step on the brakes, both brake switch terminals should now be 6v. If not, the brake switch is probably bad.

3) When you step on the brakes, the other end of the wire coming from the brake switch should have 6v up at the signal switch.

 

Good luck!

 

 

 

[straight8pontiac]

Thank you Bloo... I will check each of these with a meter tomorrow

[straight8pontiac]

16 hours ago, Bloo said:

When you step on the brakes, the other end of the wire coming from the brake switch should have 6v up at the signal switch.

This is the wiring diagram that I have for the switch. Each of the signal switch wires is spade connected to the appropriate wire under the dash.

 

Using the above diagram, I am using the white wire. My spade connection is after the brake switch label and before the solder connection on the signal switch(let's say at the words white-brake sw).

 

When we step on the brake pedal we get a zero (0) voltage reading from white wire to ground. The fuse is good and the brake switch is good.

 

Am I correct in saying that the incoming wire to the brake switch is not providing voltage to one side? How do I get proper voltage to the brake switch?

[Bloo]

It should be hot when you are stepping on the brakes. Turn key on to make sure it isn't that.

 

1 hour ago, straight8pontiac said:

 

Am I correct in saying that the incoming wire to the brake switch is not providing voltage to one side? How do I get proper voltage to the brake switch?

Probably. You'd have to check it to be sure. Do you have power down at the brake switch? If yes, step on brakes, the other terminal should then be hot too.

 

Other terminal not hot with foot on brakes? Brake switch is bad.

Other terminal is hot with foot on brakes? White wire is broken between brake switch and turn switch.

No power at either brake switch terminal? Well... then yes, the incoming wire is not constantly hot and it should be.

 

If there is no power at either brake switch terminal you have to find why. I don't have a wiring diagram for that car. One of those brake switch wires is the the white wire (I don't know if its white at that end or not. It probably is but I wouldn't bank on it). Do you have a wiring diagram for the car? Maybe a shop manual? It should be in there. Follow the other wire (not the white one) back on the diagram and see what it goes to. Look there for power. If that partial diagram you just posted is right, it goes to a fuse. Check for power there on the incoming wire to the fuse. No power? Follow back to the next thing on the wiring diagram and check there.

 

Note: Glass fuses can be bad and look good. If you haven't checked the fuse for continuity with a multimeter yet, don't assume its good just because you can see the element inside isn't blown. It could still be bad.

 

Edited November 18 by Bloo (see edit history)

[straight8pontiac]

3 hours ago, Bloo said:

No power at either brake switch terminal? Well... then yes, the incoming wire is not constantly hot and it should be.

I removed each incoming/outgoing wire to the brake switch and was not able to measure any voltage.

 

Looking up under the dash with this picture. The wire with the purple tape represents the white wire which goes to the turn signal switch to supply power. This wire originates from a taped loom of multiple wires, goes into the bakelite connector and out the right side to match up to the white wire for power. Obviously to me, no power in that wire.

 

 

This schematic came out of the Pontiac Shop Manual however I don't think it shows the turn signal switch with its six wires. I don't think that matters at this point because I am looking for power to the brake light switch. I can see the fuse just above the brake switch, but where would you say I am getting power to that line?

3 hours ago, Bloo said:

Check for power there on the incoming wire to the fuse.

That wire is completely insulated. Would I have to strip insulation in order to measure?