72 Scamp No Brake Lights...

[7milesout]

Guys,

I've read many threads and have followed recommendations. But electrical is my weakness.

One day I'm driving the Scamp and a nice passerby let me know my brake lights weren't working. I had done no mods to the scamp prior to this.

The blinkers work on both sides, all taillights / running lights all work. Blinkers work with the taillights on. And the bulbs are dim with the taillights, and bright with the blinkers. So it's not a bulb issue. But nothing happens when pushing the brake pedal.

I read that it could be either the brake switch, or the turn signal switch. I started with the brake switch because I thought it would be easier than the turn signal switch. It wasn't. There's no easy way to remove the brake switch bracket so I just had to pry the switch out.

Anywho - At this time I have replaced the brake light switch and the blinker switch and still nothing. Blinkers work with the new switch, taillights work … just no brake lights.

The thing I question is … the blinker switch only had two wires. Looks like one wire would be a ground path for one set of lights (left for example), and the other wire a ground path for the other set (right for example). I read that power to the brake lights ran through the blinker switch. But like I said, there were only 2 wires. What am I missing?

I miss driving the Scamp. But won't take any chances of getting a ticket, or worse it bashed into by an idiot (already risky enough). Any help is greatly appreciated.


7milesout

 

[Alaskan_TA]

The brake light system routes through the hazard switch, so if your hazards are on & you use the brakes the brake light signal interrupts the rear flashing lights.

You can test a new switch harness by unplugging the one in your column & then plugging the new one, or a used old one in to see if its good.

So testing them can be done with no need to tear into the column.

 

[7milesout]

Why was I under the understanding that power routed through the blinker switch? Is my comprehension skills that low? Or do other A Bodies route power through the blinker switch and I read one of those threads... Hmmmmm.

This is aggravating to have removed a perfectly fine blinker switch. The new one doesn't have the feel of the old one. I don't know if the old one was stock or not, but probably was.

Now I'm going to have to figure out how to remove the hazard switch... I'll search for a thread on that.

Thanks Alaskan_TA!


7milesout

 

[Caco2120]

Ok test 1...there are 2 wires going to the brake light switch.... if u pull them off the switch and touch them together. Do u get brake lights to illuminate? If you do, your switch is junk, or yoir pedal geometry to the pedal is off

 

[67Dart273]

The brake lights DO route through the turn signal switch. Learn to check voltage not guess and replace parts. Go to MyMopar.com and download a free service manual. some of them posted there---including the 72---came from the efforts of guys right here

MyMopar - Mopar Forums & Information - MyMopar Tools/Reference

The brake light switch should get power from the fuse panel at all times. Therefore one wire going to it should be hot at all times. Be careful you don't short it and blow a fuse. The white wire goes TO the turn signal switch. If you have it there when the pedal is pressed, double check at the turn signal switch connector into the column. If you have power there when the pedal is pressed, and the signals work, TRY WIGGLING the hazard switch and make certain it is off. if all this is in place and still no lights, you are in for replacing the switch.

AbodyJoe on here posted a nice how to on changing the ignition switch which is the "same road' as replacing the TS swtich

 

[AJ/FormS]

One thing you should know is that the contacts in the aftermarket blinker switches tend to recede into the crappy nylon switch bodies when they get warm. As when the brake-lite sw sticks on, or the hazards are on for a long time, or if you are in tha habbit of riding the brake pedal. You will see it when you separate the two halves of the switch. It can happen on the factory one as well but it takes about 50 or a 100 times as long.
I recommend you check this out before you spend 50 hours looking for an electrical problem that may not exist.

 

[67Dart273]

^^This reminds me^^ In the early 70's when I owned the 440-6 RR, it, and at least two other guys on the Air Station had failures of brake lights which turned out to be problem in the hazard switch section of the switch. I was able to pull the wheel, disable the hazard switch by chopping off the handle, and reroute 1 or 2 wires (resoldered) at the switch to restore otherwise normal operation. "Don't ask me which" that was many years ago. I still have parts of that 70 factory manual........bought at a dealer..........

 

[7milesout]

I finally had a chance to put a multimeter on these things. Here's what I have. Once again I want to mention, electrical is not my strong suit ... and electical schematics ... forget about it.

• Brake light fuse is good.
• No voltage at either side of the (new) brake light switch, meaning on the terminals of the switch. This seems to be the problem ... not the switch itself but the lack of potential on either side.
• I do measure voltage up at the blinker switch (on the left side of the blinker switch) and otherwise the lights and blinkers work as they should.

I'm sorry to be a pain guys, but this approaches my limit of electrical knowledge. I don't know where to go from here. I seriously appreciate your guidance and hope to be able to support others in the future. Loving the A-Body!


7milesout

 

[67Dart273]

I'd say you have a problem right at the fuse/ fuse clips/ wires terminating at the fuse clips. There is only a foot or a little more of wire from the fuse panel to the switch. The switch is hot (or should be) at all times

Did you download the service manual? (Post 5 above) Look up what all is on the brake light fuse and see what else is/ is not working

 

[7milesout]

Downloaded long ago. Wiring schematics are just hieroglyphics to me.

 

[67Dart273]

Well you should try and learn. I was a Navy ETR (electronics tech radar) and an amateur radio operator, BUT THE FACTORY diagrams are quite different from electronics drawings. Try and learn them as a "road map." Just pretend you are driving somewhere. Here is a sample.

Start with page 8-127, the fuse chart. Here is a section of that page, showing everything that is on the fuse supplying the brake lights

Next we move to the fuse panel itself

Page 8-144 gives you the wiring diagram index

You go down to "Instrument panel, Valiant" page 8-150 Here's a crop of the fuse panel

Now we need to track where the stop lamp switch power comes from We find the stop lamp switch depicted in the diagram, page 8-151

Notice in the diagram below, you have a "P" pink wire and a W white wire. Notice that the PINK goes up to one terminal of the HAZARD FLASHER. That is a terminal point, they are "picking off power" from that terminal. If you continue to follow that wire from the HAZARD FLASHER called D31-18P which means circuit D31 and a no. 18 wire PINK in color, you will find it goes directly to fuse "D". Maybe the terminal / wire is broke at the hazard flasher.

Bear in mind there are TWO flashers, one for the hazard, and one for turn signals. You will have to be sure you are looking at the correct one, and you can verify that with the wire colors.

 

[7milesout]

67Dart - Thank you for the time you took for that info. I'm average to good with mechanical problems. But me and electrons just don't see eye-to-eye. Thanks to your help, turns out it was just the dome lamp fuse.

I'm embarrassed to admit that, but I'm not going to make up some b.s. and cover up my stupidity.

However, now both brake lights won't work unless I have the blinker switch in just the right place. Which tells me the blinker switch is a P.O.S.

So ... I'm going to read back on this thread and see if somebody identified a high quality blinker switch. If not, if someone has a suggestion I would appreciate it. I'm going to replace that cheap switch ASAP.

Thanks everyone.


7milesout