Turn signal issue. Headlight or Dimmer switch ?

[jh23job]

I have a 1970 road runner, and after putting the car all back together I have a weird gremlin in the turn signals. I have run ground wires to every location I can think of per the wiring diagram that has anything to do with the lights, and no fix.
Here's the problem...
All lights work (key in run position), signals all work fine. Turn on the headlights, and everything works fine EXCEPT the front parking lights/turn signals. The parking lights are both on, but no blinking in either left or right position. However, the tail lights and blinkers work fine no matter headlights on or off. The last thing I can think of is something going on with either the headlight switch or dimmer switch.
Anyone have anything for me to try ?

 

[ruffcut]

Not the dimmer switch

 

[493 Mike]

Disconnect the TS switch column connector, jumper the power terminals to power up the switch and check for all 4 outputs from the switch. If that all works, check out the parking lamp connector for power to both filaments. If that all works, it's bulbs or grounds.
Mike

 

[retractable]

I just had weird gremlins working on the lighting for my 66 satelitte. Tried a ground wire to each front signal and rear lights. Nothing changed. Finally found two bulbs that would not get a good ground in their sockets. They would light but were looking for a better ground to work correctly.
It can be very frustrating. Good luck.

 

[pnora]

Sounds like you are losing the ground at each front turn/park socket. You should be able to verify that the bulb itself is grounded along with the power on the two wires feeding the bulb. My bets are you run an auxiliary ground to the bulbs brass shell and they will work.

 

[jh23job]

Checked the power at the TS connector, and all tested fine, as the rear signals work.. just the front ones don't with the lights on.
Replaced both bulbs with new, same result.
I grounded BOTH brass parking light housings directly to the negative battery terminal, same result. I'm stumped.
Any other suggestions ?
As a side note, the parking light housings are BOTH brand new, as is all wiring, etc.. so bizarre, and I'm sure it's just something simple and ridiculous..lol

 

[pnora]

Checked the power at the TS connector, and all tested fine, as the rear signals work.. just the front ones don't with the lights on.
Replaced both bulbs with new, same result.
I grounded BOTH brass parking light housings directly to the negative battery terminal, same result. I'm stumped.
Any other suggestions ?
As a side note, the parking light housings are BOTH brand new, as is all wiring, etc.. so bizarre, and I'm sure it's just something simple and ridiculous..lol

It cant be all fine. You need to ground the bulb not the housing. You also need to check for power and grounds when the park lights and turn signals are activated. A simple test light or voltmeter and a guy should be able to figure it out in a few minutes.

 

[hunt2elk]

I agree with pnora, even though you are grounding the lamp housing, that doesn't mean the ground is getting to the bulb. I have had this exact thing happen to me on 2 different cars.

 

[peabodyracin]

Seems like a classic ground problem. I've chased some bizarre ones over the years too. In fact come spring I have to crawl under the dash on my 69 RR because the brake lights seem to be doing different things every time I activate them. Good luck!

 

[oldbee]

I agree with pnora, even though you are grounding the lamp housing, that doesn't mean the ground is getting to the bulb. I have had this exact thing happen to me on 2 different cars.

Correct bulbs? It’s happened before.

 

[hunt2elk]

Correct bulbs? It’s happened before.

Yes the bulbs were correct. The problem was the ground connection where the factory relied on a crimped/compression area of metal to get ground to the bulb socket, which ultimately comes from the screws holding the housing to the sheet metal.

 

[451Mopar]

Glad you found it! usually the bad ground problem with the marker lights the indicator lights on the dash will come on with the head light (marker lights on) because the circuit grounds through the dash indicator lights when the turn signal housing is not providing the ground.

 

[jh23job]

No.. that wasn't the problem as I stated earlier. The crimped socket was a really dumb idea, but I've already made solid grounds for all of that..
I'm still chasing wiring. Everything is grounded up Front, as it is in the back end of the car.
I'm under the dash now, bypassed headlight and dimmer switch, and into the column harness.
It wouldn't be the first time I've seen something wired janky from an aftermarket harness..
I'll keep you all posted

 

[pnora]

No.. that wasn't the problem as I stated earlier. The crimped socket was a really dumb idea, but I've already made solid grounds for all of that..
I'm still chasing wiring. Everything is grounded up Front, as it is in the back end of the car.
I'm under the dash now, bypassed headlight and dimmer switch, and into the column harness.
It wouldn't be the first time I've seen something wired janky from an aftermarket harness..
I'll keep you all posted

You are wasting your time. In your first post you claim everything can work. Problem is simple and would take only a few minutes to diagnose.

 

[RemCharger]

Yes the new harnesses can be wired wrong.

 

[Speedbird]

This is a very difficult thing to say exactly what it is at a distance.
For example I've encountered strange behavior such as you describe by simply having bulbs in the wrong way.
I like to clean prints up and make simplified turn signal prints showing the inner workings of the switches.
The factory prints include things like lift gates and rear accessories.
Make it confusing.
These are for a 69 B body and I would assume a 70 isn't different as far as functions.
The importance is that I'm thinking the turn signal is separated from lighting except by the parking and stop lights. Correct?
Bulb power issue?

 

[Geff McCarthy]

FWIW, my right side turn signals both failed. Before I started to strain my neck under the dash, I accidentally discovered that the turn signal stalk needs to be held extreme right to trigger the signals. So...i hope a simple adjustment.