Turn Signal Trouble

My 71 Challenger turn signals were acting up over the summer. The left one would work fine but the right one would work intermittently. Slow, then fast then not at all. Last week, both signals cut out so I figured it was a fuse or the flasher. Replaced them both but the blinkers still refused to work. All other lights including parking lights work fine. Anyone have any ideas what the problem might be? .

seperate the steering column pull apart connector & ohm the turn signal harness with the stalk in neutral/up/down (www.mymopar.com will have the colors). confirm each light is grounded well. clean all (turn signal related) connections/terminals. Sorry nothing definite, probably just have to dig & clean till it clears up

Robert - Not sure what you mean by "ohm the turn signal harness." Am I checking for open or closed circuit? My guess is neutral stalk - open, up/down closed?

with the stalk in neutral there should be continuity between the white "in" wire which comes from the brake light switch to the 2 "out" wires to the dr/pass brake lights (which are the same filaments in the 1157 bulbs as the TS filaments). this is when you hit the brake (& stalk in neutral) the 2 rear brake light circuits light up). with the stalk up or down one of those out circuits is redirected by the TS harness to the flasher which ain't telling you much as I am rusty on diagnosing further on that. might be a loose connection in the TS switch harness & it'd be good to confirm/elim that area as a start

Are you sure you replaced the correct flasher of the two? One for turn and one for emergency lights.

I didn't know thee were 2 flashers. The one I replaced was under the steering column by the fuse box. Where is the other one?

Should be at the ashtray area maybe attached to the ashtray bracket.

the one side was out even when the flasher was flashing "normal" so there is poor continuity somewhere (including ground path potential)

I have had flashers go bad and one side of the turn signals didn't create enough resistance to make it work.

make sure everything has good grounds

Robert,
You gave me some good info to work off of. I changed both flashers and still no blinkers. I checked continuity between the white "in" wire which comes from the brake light switch to the 2 "out" wires to the dr/pass brake lights (which are green and brown) and the circuit is open on both sides. Maybe the turn signal harness is bad? All parking lights are working fine, no dimming so I guess they are well grounded. Going to pull the steering wheel and can and check the TS wires/mechanism.

make sure you check on both sides of the harness connection. i have seen just that connection be a source of unending frustration over the years, while guys replace turnsignal switches, and the problem remains because the terminals in the connection to the harness have issues.
before you pull the switch, unplug the connection and check just the switch wires. if that works out, chances are the switch is ok. [no real guarantee, but just maybe] then, look very close at the harness connection for issues such as corrosion, loose or woolied up terminals, or cracked wire insulation.

Before you go much farther, why don't you just replace all the 4 bulbs with new ones. Try that. A seemingly good bulb can be the cause. Plus, its real easy.

I used to teach troubleshooting on complex systems. Try easy things first. Also, try to fix just one side, not both. If its a common problem, it will show up. Lots of folks like to look for commonalities. If you have two problems, you'll be working a long time.

So, neither headlight works, must be something common, eh? No, after spending time checking switch and dimmer, turns out both bulbs bad. A long time ago, but I learned from that.

I didn't own a meter at the time, and that didn't help. These days, they give them away at Harbor Freight.


Good luck.

I'm going to work on the problem tomorrow. Changing all of the bulbs is a good idea. But if Robert is correct, I should have continuity between the "power in" white wire and brown and dark green tail light wires with stalk in neutral. I checked and I have an open circuit on both wires. Also, the flasher button/switch is jammed and I can't get the flashers to work so maybe the problem is related.

take care of this before you do anything else

Like Robert says fix the stuck switch before you do anything else. Turn signals won't work as long as that's stuck.

Update. I took out the signal mechanism and cleaned the contacts the best I could, and replaced the emergency flasher and directional flasher. . I also got the flasher switch to move in and out but the flashers do not work. The left blinker works fine now, but when I put the right blinker on, the amp needle swings hard to discharge each time the directional flasher clicks. Neither the front or rear right blinkers work with the flasher clicking. If I leave the right blinker on for more than 20 seconds, I blow the radio/backup fuse and the hazard/stop lamp fuse. I checked all bulbs and grounds (that I know of) and they look good. However, the right front blinker/parking lamp does not work either in blink mode or when I turn on the parking lamps. But the fender side marker light works which I'm sure is hooked up to the front park lamp. I changed the front right blinker/park light housing and bulb thinking maybe an internal short, but it still doesn't work. All other lights work including brake lights. Is it logical to assume my problem is somewhere in the harness between the front right blinker and fender light? Can the problem still be with the directional switch?

Man that's a tough one! Yes there is a dead short or very heavy draw on the right side blinker that is swinging the needle to discharge when it clicks & likely a seperate open. I hate to recommend a new TS harness assy. I think I would seperate the TS harness pull apart connector again & with some jumpers & write down the schematic from www.mymopar.com & feed 12V in seperately to the right side to pin it down. Not much help & I am just thinking out loud. I would search downstream from the right flasher for the ground. EDIT you might take out the TS harness completely (at least seperate the mechanism under the steering wheel from ground) then plug it in & if that changes anything

Robert, can you add clarity o this " EDIT you might take out the TS harness completely (at least seperate the mechanism under the steering wheel from ground) then plug it in & if that changes anything"

Short of tearing the whole wire harness apart from dash to turn signal, I don't know where to go from here.

I was thinking that if you removed the stalk then unbolted/removed the plastic cam/terminal assy from under the st wheel then mini bolted the stalk back on & operated the assy held up in your hand that that would elim a potentail ground fault at that location. Otherwise with the gauge pegging when the R turn signal flashes there is a dead short downstream on that side.

YIKES!
I just noticed that the map light comes on when I press the brake pedal.[censored]?
Going to have to dive deep into this one.

that's NOT good.

If the dome light goes on when stepping on the brake pedal of a 67 GTO, that means the brake light fuse is blown. Could just be something similar.

Interior lights only come on when both fuses are blown. I replaced the fuses and now I'm back to square 1. Everything works fine except left blinker. Keeping it on blows the fuses. The dash wire harness has never been cut or messed with and I clean the bulkhead connectors with contact cleaner from time to time. I'm going to start off by replacing the directional switch in the column. I guy I met at a show yesterday said he had a similar problem and it was the directional switch. I see many after market switches out there. Can someone recommend a good source?

Yeah, weird things can happen at the directional switch.

If this helps illustrate my comment: A guy told me in traffic one day that the left rear brake light wasn't working on my '67 Satellite. Turns out the screw holding the directional switch stalk got loose inside the steering column. The force of gravity on the loose directional stalk moved it downward close enough to the 'Left Turn' detent, that it cut power to the left tail light but ONLY WHEN BRAKING. Weird but true. All I had to do was tighten the stalk screw and the problem was fixed.
Best, - Art