greetings all, i have an issue with my 1971 914. the turn signals function normally with the headlights off, but don't function at all with the headlights on. any thoughts on where to start would be greatly appreciated. all the bulbs are good and all the wiring seems fairly stock. thank you

Do the 4-way flashers work with the ignition key off and the headlights on?

Here's the pertinent wiring schematic for the turn signals. The headlights don't come into play here.

You might have a ground problem somewhere.

with headlights off, ignition off, 4 way flashers function normally. with headloghts on, ignition switch off, left rear and right front flashers function but not there counterparts?

Is it with headlights on or just the parking lights on?

Check all the bulbs to make sure they are making good contact in the sockets.

The bulbs should be the 1157 type as well with the dual filaments.

Also when the lights are flashing, make sure its the bright filament flashing and not both. If both are flashing then the bulb isn't making good contact with its ground lead.

loss of signal functionality occurs when the headlight switch is in any position qther than off.

bight filament when the lights are for flashing, headlights on both filaments on left ide light only dim eilment on right light.

Sounds like you have some socket issues with the ground.

Are the sockets nice and clean?

Clean the sockets; make sure the bulb base is clean.

With everything off and the bulb out, measure resistance of the socket to ground. Not the terminals at the bottom; the base metal of the socket. These should be at ground potential so you should measure just about zero ohms.

will try to do tomorrow thanks for the assistance

Verify the wire connections with both front and rear turn signal buckets. Since the light is dim in the error condition, it is probably getting power feeding back through some other bulb, which means someone has the wrong connections.

--DD

....... or the wrong bulb. A double filament bulb in a single filament socket, or vice versa, will cause that problem.

The Cap'n

Sounds like a ground problem to me. If a ground is open the circuit fill find ground through the lamp filament while the lights are off. When the lights turn on, the circuit turns positive and will no longer flow current backwards through the circuit.

A DC circuit only needs a less positive path for current flow. This is why wacky things happen with bad grounds. Check them all!

Analyzing the circuit schematic, I'll put my $ on the wrong bulbs too

I have not looked at rear lights yet but front turn signal bulbs are double filament. is this not correct?

Yes.

The Cap'n