Weird brake light problem

[carguybradd]

Hey everyone - I just joined this forum and I'm hoping someone here can help me out.

I did a quick search on this but couldn't find the same problem I'm having with my '70 Challenger. My left brake light won't come on at all, although the tail lights and turn signal on that side work just fine, so I know the bulb & wiring to it are OK. It doesn't matter if the lights are on or off. The right one works normally. 

A buddy thinks it's probably the turn signal switch, which is a new one on me. I may be new to this forum but to wrenching on cars, still there's always something new to learn, right? What do you guys think?

Please help me out - I got a verbal warning from a cop so I won't drive the car again until it's fixed, and I REALLY want to drive it again (to get my "fix"). 

Thanks,

Brad

[DoNotChallengeHer]

A friend of mine was having a similar problem with his Charger. It was his turn signal switch. I've heard about this problem from other Mopar friends and they said it was the turn signal switch too.

[JayBee]

Did you make sure the socket is grounded well to the housing? I had issues once with this too and ended up sanding the mating surfaces of the socket and housing which fixed the problem. Unfortunately I can't remember if it was just the brake light or brake/signal and tailight. Good luck and let us know what it turns out to be.

[carguybradd]

Thanks for the comments guys. I did check the ground on the sockets and it's good - that was the first thing I suspected.

I pulled the steering wheel today and had a look at the TS switch. It looks OK to me (no broken wires or burn marks), but who knows?

[Chryco Psycho]

I have often seen this , it is the TS switch , the brakes lights go through the switch & are interupted for turn signal
 Standard makes  the replacement switch part # TW7

[carguybradd]

Thanks Chryco Psycho. That's exactly what my buddy was telling me, I just like to to be thorough. I guess I should listen to him, huh? 

[Chryco Psycho]

sounds like he knows his stuff

[MEK-Dangerfield]

sounds like he knows his stuff

   

 The brake light and turn signal use the same filament in the bulb, so I doubt any grounding issue here. Before putting in a new turn signal switch, check to see that you have an 1157 bulb in the socket. The only other explanation I can think of is somone might have hacked up your rear wiring harness for some reason. I had some genious(sarcasm) do that to my car right behind the driver's side kick panel. What they were thinking I truly don't know.   


   Mike

[Slotts]

I had some genious(sarcasm) do that to my car right behind the driver's side kick panel. What they were thinking I truly don't know.   
   Mike

 
Isn't it funny how with so many electrical problems can be correctly diagnosed, in theory, when sometimes all it results in is a wiring hack job. 
Mike, I think the seventies weren't kind to a lot of folks.  

Slotts

[carguybradd]

Thanks for the input. The LH tailamps weren't working at all when I got the car a year ago, so I checked the bulbs then and found it was just a corroded grounding problem. The harness (at least what I can see of it) looks to be original and unmodified in any way.

I guess I'll order a TS switch when I get back from a business trip later this week, and go from there...

[MEK-Dangerfield]

I guess I'll order a TS switch when I get back from a business trip later this week, and go from there...

Have fun pulling that crush can off the steering column if you haven't done that before. You DEFINITELY need a "puller".   


  Mike

[carguybradd]

Been there, done that! The only problem I ever encounter is getting the steering wheel puller in there and then trying to start the bolts with my big hands in there too!

[Chryco Psycho]

I use a regular damper puller with 7" bolts & a longer center bolt

[carguybradd]

Here's an update for those who care:

The new TS arrived in the mail last week so I changed it out this past Sunday. Had to trim the flasher knob, as expected, and also noticed the old one was "modified" in the same way. OK, someone's played this game here before...

Anyway, before reinstalling the steering wheel I decided to hook the battery up & test it out. Left turn signal? Check. Right turn signal? Check. Flashers? Pfzzzt! - Did I just see a wisp of smoke come out of that new flasher switch!? 

Come to find out that I blew two fuses: flashers and brake lights. I replaced the fuses and decided to double-check to see if the new switch was wired correctly (luckily I still had the old one next to me). The wiring checked out fine, so I decided to test things out again, step by step, to try to figure out where the problem might be. To my amazement, everything worked fine!

Well, that was short-lived. I took the car out for a spin (after putting the steering wheel back on, of course), and one block from my house I applied the brakes while pulling up to a stop sign. As I did so, the radio momentarily went dead, and then was fine again. I knew at that moment I had blown another fuse, and sure enough, the brake lights again! I put another fuse in (I have stock in Buss 20-Amp fuses, don't you know!  ), and proceeded to recheck everything. This time, all is well again, including with the engine on or off, the lights on or off, and the radio on or off. At this point I switched her off and put the car cover back on.

OK, I understand that fuses exist to protect the wiring, and blow if you have a short. My next step is to go over the brake light harness with a fine-toothed comb, but I guess this is to be expected with a 40-yr-old electrical system (and I know enough to carry extra fuses ). I'm wondering if anyone out there has had any similar problems, and if so what was the cause? Believe it or not I'm actually pretty good at electrical trouble-shooting & repairs, but it might help me out to hear from anyone who's had similar problems. 

Thanks,

Brad

[Chryco Psycho]

wrong bulb in a socket can do it , for example using a using an 1157 in a single pin socket or the other way round , using an 1156 in a 1157 socket , make sure the wires at the brake switch are not grounding out