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Hi Don,

Well, I checked out the stop light switch on my Packard and found one of the wires was loose. After I tightened it back up, I had a good connection for the front turn signal that didn't work previously, and BINGO, now it does. But unfortunately, it didn't solve the problem of the brake lights. I went online to check O'Reilly's Auto Parts as well as NAPA for a replacement switch, but they don't carry the one with the two screws in front. What is the model number or reference number that I can use to track it down?

Thanks,
Steve

Look at my earlier response….I put a link to the switch I bought at O’Reily’s that includes the model number.

I’m not familiar with the wiring for your aftermarket turn signals. I loose connection at the brake light switch could absolutely cause the brake lights to not work, but I don’t see how it would impact your front turn signals.

That leads me to question if things are hooked up correctly. I wouldn’t think that any wires associated with your front turn signals would be connected to the brake light switch.

Okay….let’s go through how things would work without your turn signal controller…

In this case, you would have a “hot” wire going to the brake light switch. Then, the other terminal of the brake light switch would go to your brake lights. So, if you jumpered the terminals, your brake lights should come on.

Now, let’s look at how it works WITH your turn signal controller…

In this case, you still have a ‘hot’ wire going to one terminal of the brake light switch. But now, the other terminal of the brake light switch goes to the turn signals controller. Then, you should have two wires coming from the controller…..one to each of your brake lights.

Then, you would also have two more wires coming from the turn signals controller, one for each of your front turn signals.

The controller then has the “brains” to turn on the front and rear turn signals based on the turn signal lever position and turn on the brake lights when the brake pedal is pressed.

So, I’m now wondering if you have a bad connection at the controller or if the controller has failed.

This leads to a different path of troubleshooting…..

Am I right to assume that your rear turn signals are using your brake lights? That would be typical. If so, do the rear turn signals work and just the brake lights do not? Or do you have separate bulbs for the rear turn signals and brake lights. That is….do you have two or three bulbs on each side in the rear……taillight, brake light, and turn signal ……or…..taillight, and brake/turn signal?

All the suggestions of using a wire to bypass the switch to eliminate it as the problem are valid and should be done. Checking the wiring for any other loose or broken connections is also a good idea. Before getting involved directly in the turn signal switch and that part of the circuit, make sure yours is one of those that does take the brake signal and split it before passing it on to the rear bulbs. If there are only 3 or 4 wires in that black cable going up to the switch, the brake signal does not go thru the switch and the problem is somewhere else but if there are 7 to 9 or more wires then if you don't find any more loose or broken wires it is very possible there is an issue in the switch. Even factory switches had problems with warped contact support pieces or the contacts corroded and oxidized resulting in bad connections thru the switches.

Also look at the entire loom heading to the rear of the car and see how the bulbs are fed. If you see new type wires or a loom that is distinctly different than the typical woven loom of the era then it is probably coming from some kind of junction point with the turn signal switch but also look for some inline connectors. Typical connector types of the era can be either round or flat bakelite plastic items maybe an inch and a half long. Depending on function there can be different configurations where 2 to 4 wires will be plugged into a connector. Sometimes a wire can get pulled out or the connectors were also vulnerable to corrosion and a resulting bad connection if they got wet.

If you can find a manufacturer or a model number on the case of the turn signal switch it might be possible to find a wiring diagram online.

Hi Don,

Yes, I got your reference for the proper Stop Light Switch at O'Reilly's, thanks so much.

Per your last suggestions: I made a jumper wire and attached it to the two terminals on the Brake Light Switch, (see attached picture). (Since I'm working alone, I jury-rigged a couple of pieces of wood to depress the brake pedal) while I checked the rear brake light pedal. Nothing!

To answer your question about taillight bulbs, there are two bulbs in each rear taillight, one on top, one in the middle. When I move the turn signal handle on the steering column left or right, I get turn signals from the middle bulbs. When I turn on the lights, I get taillights from the top taillight bulbs and headlights too.

Since I get no brake lights with this jumper wire configuration, I assume then that the "Stop Light Switch" itself is bad and needs to be replaced. Right?

Let me know your thoughts before I head over to O'Reilly's.

Thanks again,

Steve

Quote:

Steve, no, that's not correct. If your brake lights lit up with the switch jumpered, you would know the switch is bad. All the switch does is connect the two wires (input and output) when you apply pressure by stepping on the brakes. Since you connected the wires and the brake lights still didn't light up, you have a different problem, and you don't yet know whether the brake light switch is good or bad.

Take a voltmeter, connect to ground, and then check the voltage at each terminal of the brake light switch. If you have power at one (6V) and no power at the other, you're off to a good start. Trace the wire that doesn't have power, and try to determine how it goes through your blinker system, and that is likely the culprit.

If you have no voltage present at either terminal, trace both wires, figure out which one is supposed to have power, and determine why it doesn't (blown fuse, etc). Once you verify you have power going to the brakelight switch, then you can test it again determine if the switch is bad, or if the problem lies elsewhere.

Quote:

No need to press the pedal as that’s the point of the jumper to bypass the switch. Just leave on the jumper for your other tests.

I’m not sure if it’s been mention but poor grounding of the light housings also often contribute to this type of problem but not likely on all lights at once. Did you check that one of the switch terminals is getting power? With the jumper in place, measure between the pins (either one) to see if there is a good solid reading. As already stated a couple times, if there is power there, then it’s something in the wiring to the lights or in the aftermarket signal switch. If no power, it’s the wiring to the light switch where it’s supplied.