Mechanical brake switch for 47 Plymouth

[Norm's Coupe]

I have a Watson brake switch too on my 48 coupe. As Don & Tim pointed out' date=' it sounds like you have a wiring problem. If you still have the old original wiring to the switch you should cut at least an inch or two off from the bottom, then add new wire to the switch. That way, you'll get rid of the old wire at the weakest point where it connected to the old switch. Also, check to see if you have a headlight relay in your car. If you do, it also has a fuse and you may have blown that one too.[/quote']

Tim, I guess that's where we disagree. In my original post, I did agree with you and Don, and still do. In this case he has a wiring problem. However, since many cars did have a relay installed after they were built, that he should look to see "IF" he had one, then check that fuse. All you have to do is follow the headlight wires under the hood to find it. So.....even though it may not be in the original wiring diagrams, it could have been his problem. And, in this case, it would be a lot easier to find that little relay and check a fuse than trying to trace a bad wire someplace. Then if he didn't have the relay, he should then check his wiring. So.....there is nothing confusing about that, it's pretty straight forward. In addition, even though it's not in the original wiring diagrams, it is a period correct option/add on and a good possibility of being on the car. From the looks of the one on my car, it looks like it was installed by a professional shop about the same time the car was built. The original owner probably had it installed not long after buying the car.

[central52]

It's me, Central52. The relay switch discussion was informative and necessary for me to check it out, so I don't mind all that chatter. Now that I resolved the no lite problem because of the short fuse, back to the brake lite switch problem. How can I check the mechanical switch itself to see if it's defective? I've already installed it, (a royal pain to do), so if I have to replace it, ahhhh! I was thinking, the two wires in the old presssure switch were there all these years with no shorting out. I pulled them out to attach to the mechanical switch, I can't tell which is the hot one, and the other to the brake lite itself.

Being underneath the car, with my hand in a very uncomfortable position, I took one wire and attemped to attach it to the mechanical switch. I'm not sure what I hit, either the body of the switch, or one of the prongs on the switch, that's when I got the spark.

Also, can I check the two wires I pulled from the hydraulic switch by attaching jumper wires to the battery? if that works, would the brake lite in the trunk go on? Ed P.

[Plymouthy Adams]

you can test the two wires on the car by just jumpering them together...should lite the brake light..it should spark a bit if your light is working..but should not pop a fuse...if sparks and blow another fuse..then the one going to the rear is grounded somewhere.

As for the switch..either post should be fine for connecting..this switch is for power only and is not ground related..its purpose is to "jumper" the same two wires in above test internally. As for what one is hot..get a test light..hook the clip to the chassis..use the probe on the two wires..only one will be hot..if you do not have a test light..make up one..quick one can be had from a modern car side marker pigtail..can save you a bit of trouble. Does this car have turn signals?

[james curl]

If the battery is hooked up and all the wires are in place, the bare ends of the two wires that were unpluged can be touched together and the brake light should come on. The switch is only a normally open switch which brake fluid pressure closes to complete the circuit. Think toggle switch, when in the off position only one wire is hot in the on position both wires are hot just as touching the two bare wires together. The answer is yes.

[B-Watson]

Chrysler replaced General Motors (United Motors, DELCO) as a supplier of electrical equipment in 1935, switching to Autolite. Autolite was used until Ford bought the rights to the name along with a spark plug plant in 1961. The remnants of Autolite became Prestolite, and Chrysler used Prestolite from that point. At this time Chrysler got into building their own starters, alternators, etc. Both Studebaker and American Motors switched from DELCO to Prestolite around that time, as well.

The switch to Autolite occurred as Walter Chrysler did not like using parts built by his main competitor. Autolite expanded into spark plugs to secure Chrysler's business and also produced starters, generators, distributors and ignition parts.

Not sure when Chrysler began using Ditzler (PPG's paint division) but I suspect that was in the 1930's as well. Their paint chip charts always had complete Chrysler listings, whereas DuPont (GM's biggest shareholder until the early 1950's) did not.

By the way, Plymouth began using enamel car paints in 1935, switching to all enamel in Detroit for 1936. The Los Angeles plant continued to use lacquer to the end of the 1939 model year. Dodge, DeSoto and Chrysler all switched from lacquer to enamel for 1939.

Bill

Vancouver, BC

[central52]

I did what was suggested. Touched the two brake wires together, and, lo and behold, the trunk brake lite went on. So, I'm assuming there was no way I could have ruined the mechanical switch, when I originally shorted something out. It's freezing outside now, and I'm going to wait a day or two before I go underneath car to connect those wires to switch. As for the other question about directional signals, I don't have them, but would like to put them on, using the front parking lites for the front signals, and the rear tail-lites for the back ones. Since I have the trunk brake lite, I will keep it as such, and not complicate the set-up with the two rear tail lites. Any suggestions as to where I can get a SIMPLE kit to do this? Ed P.

[steveplym]

Central,

Basically what I did was buy the 7 wire turn signal switch. Ran wires for the two frt turn signals out to them and ran the rear turn signals out to rear taillights. My car has double filaments in the rear tail lamps so that was pretty easy. If yours has double filaments you can do the same, or add the double filaments, pretty easy to do.

Also the other thing I did was with the double filaments you can run brake lights to the bright side of the side lights as well. The turn signal switch has a wire that is set to run from the brake light switch. I just spliced this wire in to the connector on the other side of the mechanical switch. Kept the middle light wired as well and magically when you press on the brake all three lights light and since it is wired thru the turn signal switch it will send intermittent power to the side you are trying to signal to. That way all the rear lights don't have power to the at all times when the brake lights and turn signal lights are on.

The wiring diagram for the a/m signal switch is fairly easy to follow.

[central52]

Steve, when you say "double filament", does that mean just the bulb itself, not the wire and socket that it's in? And as for the 7 wire type, any such kit as advertised on e-bay or sold elsewhere will do the trick? I appreciate your input. Thanks, Ed P.

[Plymouthy Adams]

Most of these cars were produced with single filiment bulbs..that is one contact centered at the base of the banonet. The socket will reflect a single wire also centered in the base of the fixture. You can upgrade to dual filiment bulbs and double wire bases by removing the single insulator and installing the dual..these are sold at lots of places...will be indexed with four holes so you can match your wiring to your socket and bulb. This will allow the use of outside turn signal and running light..leaving your center stop light very much like todays third light setup..(do you see forward thinking here)

That was why I also asked earlier about turn signals..if they were affixed aftermarket it could very well have affected the operation of your brake light wiring as there are a couple different aftermarket signal setups and wiring. One could have couple options for turn and brake operating together while retaining original centered third light for stop indication as intended...

[Norm's Coupe]

I did about the same thing as Steve did. Bought a 7 wire aftermarket turn signal switch. Added a jumper wire to the center brake light so it would only work as a brake light. The others come on with tail lights, brake or turn signal. Also had to change tail light bulbs to double filament. Tail lights stay lit when turn signal is on.

[central52]

I'm baaack, again, Central52. Well, I hooked up the mech. switch. Connected the wires to switch. No sparking, no shorting. Fine, so far. I look back at trunk brake lite, and it's on. I press the brake pedal, and it's still on. I check underneath to see how the pivot arm is set, and it appears it's correctly positioned. It's pushed in when pedal is up, and when I push pedal down, it opens up. Is the switch defective, or I missed something hooking it up? Ed P.

[Don Coatney]

I'm baaack, again, Central52. Well, I hooked up the mech. switch. Connected the wires to switch. No sparking, no shorting. Fine, so far. I look back at trunk brake lite, and it's on. I press the brake pedal, and it's still on. I check underneath to see how the pivot arm is set, and it appears it's correctly positioned. It's pushed in when pedal is up, and when I push pedal down, it opens up. Is the switch defective, or I missed something hooking it up? Ed P.

The switch arm should not be contacting anything when the pedal is at the top position.

[steveplym]

I agree with Don, may not have arm adjusted right.

With mine when there was tension on the switch it was "off", and when you pushed down the tension was off and the brake light should be on.

Picture is fuzzy, but you can see the position of the switch. This is a pic taken facing towards the front of the car from underneath.

[central52]

Thanks guys, those two pics of switch looks different from what I have. Who manufactured those. I guess it doen't make any difference, since they all work the same way. But I'm curious as to price compared to what I paid, $22.00.

Anyhow, I'll go underneath to check the positioning again. I think that might be the problem. Ed P.

[Don Coatney]

I paid, $22.00. Ed P.

I have had my switch sitting in my parts stash for about 40 years. No idea what I paid for it.

[Norm's Coupe]

Thanks guys, those two pics of switch looks different from what I have. Who manufactured those. I guess it doen't make any difference, since they all work the same way. But I'm curious as to price compared to what I paid, $22.00.

Anyhow, I'll go underneath to check the positioning again. I think that might be the problem. Ed P.

I believe the switches like Don has are a lot less. They are still available at your local parts houses. I have the Watson switch too. The only difference between the one like Don has and the Watson switch is the adjustable arm. With the one like Don has you have to position the switch before mounting because the arm isn't adjustable. With the Watson switch you have more room for adjustment after mounting with the adjustable arm. The instructions that comes with the Watson switch will tell you how it's supposed to be adjusted.

[steveplym]

Thanks guys, those two pics of switch looks different from what I have. Who manufactured those. I guess it doen't make any difference, since they all work the same way. But I'm curious as to price compared to what I paid, $22.00.

Anyhow, I'll go underneath to check the positioning again. I think that might be the problem. Ed P.

I paid $22 to Watson Street works last summer as well. I figure money well spent instead of having to bleed the brakes each time my hydraulic switch went out.