So this problem only occurred after you put the new switch in or were you having the same issue with the old switch?

 

Had to read this a few times and initially was going to say you have a bad TS switch as many aftermarket/repro switches are CRAP (and that may be your issue). But I think that the issue may be at the left TS/tail light bulb/socket. The TS/tail light bulb is a dual filament bulb with each filament powered from a different source. The tail light circuit does NOT go thru the TS switch, however the TSs and tail lights share a common ground. If there is a problem with the ground at that bulb/socket then sometimes one filament can get a weak ground thru the other and appear to work - until the other filament is powered and then the first one looses ground and goes off. I would check the bulb and socket. Try swapping the rear bulbs L-R.

Good luck
Paul

 

The turn signal switch is a funky little bugger. Understanding its function will help diagnose problems.

Generally speaking, there are 2 power inputs, one from the brake lamp switch, and one from the turn signal flasher (yes, I skipped the horn and hazards for simplicity's sake).

In the "neutral" position, the T/S switch provides a closed connection between the brake lamp switch and the left and right rear stop & turn bulb/filament.

When a turn signal is selected, the above connection is interrupted, for one side and, simultaneously, a connection is made between the turn signal flasher and the particular side's front and rear bulb/filament.

Since the turn signals are an "switched ignition" operation, you can leave the ignition "off", step on the brake, and if you select a turn signal the brake lamp will go OFF on that side. I use this as a quick check...usually if this checks out okay then you can assume the T/S is functioning.

If you have a brake light that's out regardless of T/S switch position, chances are it's a wiring/bulb/socket issue. Quick checks include swapping bulbs from side to side to see if the problem remains on one side or follows the bulb. If it follows, replace the bulb. If not, grab a wiring diagram and start checking from the T/S switch toward the offending lamp. For instance, if it's the left rear brake lamp not working, block the brake pedal or switch so it stays on, and probe the left brake/turn wire coming from the switch at the steering column connector, then the rear light harness connector, then the lamp connector, until you find the "no power" issue.

 

The OP said the tail light goes out when he moves the TS switch lever. Since the tail light circuit does not go thru the TS switch I dont see how it could be the switch. But I can see how it would be a grounding issue where the tail light filament is trying to ground thru the TS filament - read my post.

Paul

 

Ok - thanks for the details.

I'll go through the grounds at the socket and the wires running to ground to make sure they're all good. I did swap bulbs and the conditions remained the same.

I still think something is up in the TS switch/area. While driving, when I signal right, the right front signal, dash signal, hood signal and rear light flashes. When the right signal is canceled, all lights stop flashing - except the rear light. I have to position the turn signal lever so I see the left signal flashing, then just back the lever off, only then does the right rear stop flashing.

Along with the new TS switch, I installed a wood grained steering wheel. I dont think there are any specific components to be mounted under the wood grained wheel in the TS area that differ from the factory wheel.

After I go through it all, I'll post back the results.

 

I did swap bulbs and the conditions remained the same.

Clearly there is an issue with that socket and/or its ground.

I still think something is up in the TS switch/area. While driving, when I signal right, the right front signal, dash signal, hood signal and rear light flashes. When the right signal is canceled, all lights stop flashing - except the rear light. I have to position the turn signal lever so I see the left signal flashing, then just back the lever off, only then does the right rear stop flashing.

This is an entirely possible TS switch failure mode as the TS switch uses separate contacts for the front and rear TS lamps. If one set is not moving/contacting correctly you can get the situation you describe.

^^
IMO you appear to have two distinct issues.

There are some relatively simple tests you can do with a few jumper wires at the TS switch connector to 100 percent rule in/out a failed TS switch.

Paul

 

This is a confusing thread.
But besides that, "When the right signal is canceled, all lights stop flashing - except the rear light." How does THAT happen? I've been around the block a few but that's a new one. Front and indicator stop flashing but the rear keeps flashing until fiddled with. That must be one screwy turn signal switch.

 

Turn signal switches can be screwy. I had similar problems with rear lights. There seem to be at least 2 different contacts for each turn signal lever position. One for "lane change" and another for automatic cancelling. Twice I was able to diagnose a bad switch by banging on the steering column while watching the reflection of the tail lights in a window and operating each possible contact in the turn signal switch in various combinations with the brake pedal.

 

I removed the steering wheel. everything works fine. still a lot of drag when operating the TS lever. Guess I found the area to focus on. I really dont want to shell out more $$ for another tilt column TS switch.

 

I just had smoke come out of mine TS switch .... these repros use copper where they should use brass.

$100 part didnt even last a year


anyone can recommend a better option?

 

 

looks like the only one i've found carried by the major online sellers is the scott drake one - which varies from $100-$120

68-69 TURN SIGNAL SWITCH -USE TILT WHEEL C8SZ-13341-B
Mustang Turn Signal Wiring - Tilt 1968-1969
https://www.summitracing.com/parts/sdk-c8sz-13341-b/overview/year/1969/make/ford/model/mustang


this one says original tooling - so maybe better?
Switch - Turn Signal - Tilt / Tilt Away Column - Repro ~ 1968 - 1969 Mercury Cougar / 1968 - 1969 Ford Mustang (41748) at West Coast Classic Cougar :: Specializing in 1967, 1968, 1969, 1970, 1971, 1972, and 1973 Mercury Cougar Parts