1971 right side markers dim when lights on

[tticks]

On my 71 all of the stop and turn signals work correctly when the headlights or parking lamps are switched off. When switched on the right side marker lights go very dim. At this state the front and rear turns work but the rear turn doesn’t sequence although It sequences normally with lights off. With headlights switched on a press of the brake pedal instantly lights the left brake lights as it should but the right instantly sequence once until on.
when the headlights are on the right signal indicator is illuminated which tells me the normal path is interrupted.

I’ve studied the heck out of the schematic I have and it’s simple but omits what goes on inside the sequencer and column switches. I’m unable to see visibly and understand how the circuit is completed with the park lamps powered. Really scratching my head. Could use some tips.

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[cougarsunlimited]

The 1971 side marker light wiring is unique to the 1970-71 Thunderbirds, 1970-71 Lincolns, 1970-71 Cougars, and 1970 Mustangs..
The side marker bulb ground path passes through the front turn signal bulb element.
This arrangement causes the side marker lights to flash in unison with the turn signals, until the headlights are turned on.
With the headlights and/or running lights on, the side marker lights flash the opposite of the turn signals and
the bulb current flows the opposite direction.
Note: non-bidirectional LEDs will not work in the side marker sockets because of this reverse current flow.

If the ground path through the front turn signal element is bad, it could cause the side marker light to glow dimly.
It will also affect the sequencing on that side.

Verify that the front right turn signal bulb socket is grounded and has the correct 1157 bulb installed.
If front LEDs have been installed, an LED side marker adapter kit (D0WY-15A434-LSM) must be installed for all 4 side markers.
This kit redirects the side marker light ground.

 

[tticks]

The 1971 side marker light wiring is unique to the 1970-71 Thunderbirds, 1970-71 Lincolns, 1970-71 Cougars, and 1970 Mustangs..
The side marker bulb ground path passes through the front turn signal bulb element.
This arrangement causes the side marker lights to flash in unison with the turn signals, until the headlights are turned on.
With the headlights and/or running lights on, the side marker lights flash the opposite of the turn signals and
the bulb current flows the opposite direction.
Note: non-bidirectional LEDs will not work in the side marker sockets because of this reverse current flow.

If the ground path through the front turn signal element is bad, it could cause the side marker light to glow dimly.
It will also affect the sequencing on that side.

Verify that the front right turn signal bulb socket is grounded and has the correct 1157 bulb installed.
If front LEDs have been installed, an LED side marker adapter kit (D0WY-15A434-LSM) must be installed for all 4 side markers.
This kit redirects the side marker light ground.

I’m very grateful for your input on this. I have the cougars unlimited sequencer and led tails and have been happy with them. Only the tails are led to clarify. I got the impression from the schematic I have that the ground path had to go through a lamp if not something latent to the drawing. The front turns both work perfectly with and without park/headlights. So far last weekends go at it I cleaned two grounds at the front corners of the engine bay. Pulled all the lighting connectors apart to inspect for corrosion in the engine bay. I swapped all the bulbs from right side to left and got no improvement. I will dig deeper into the front corner and report back.