FM73project

I've sorting thru a 79. I've gone thru all the lighting and have everything working but the drivers turn signal. It lights up but doesn't flash, the passengers side works fine. Could this be a grounding issue, or am I missing something obvious. Thanks in advance..

SwampeastMike

Check all of your bulbs on the driver side to be certain they are they are both good and the proper type. The front should be #1157 (amber), the rear should be #1157 (clear) and the front marker #168

If the flasher doesn't have enough current passing through it may not heat sufficiently to open the contacts.

Both turn signals operate from the same flasher and the flasher is between the fuse and switch in the circuit so if one side flashes but the other comes on steady it would sure seem that the flasher isn't seeing sufficient current.

Do ALL of the parking lights come on with the headlight switch at the first "on" position? If so then a grounding problem is unlikely.

vbgod1

I would suspect a bulb not working somewhere.

DUB

Actually from my experience. If the park lights do shine...BUT when you try your turn signals the system goes crazy...then it IS a ground issue.

The reason being the light bulbs are dual filament and using the same socket as a ground..and that is why the park lights will work fine because it is finding a ground path through the other filament...And the turn signals can be working fine for the same reason...BUT...when the headlights are on and you use the turn signals.,..THAT is when having a good ground is imperative.

I would be verifying a good ground and light bulbs in the front of the car.

Amber light bulbs are actually part number 1157NA.

DUB

FM73project

I've replaced all bulbs and replaced taillight sockets due to broken and corroded grounding tabs. I have seen a lot of corrosion on all electrical connections, so have been cleaning all with contact cleaner as I come across them. I think I will try cleaning the flasher connection to see if that works. I appreciate your help.

SwampeastMike

So all four (indicator, main front, front marker and rear) come on steady for left turn but all four both come on and flash for a right?

If so, and provided everything is wired according to the schematic, you can eliminate lack of grounding as a problem by removing the driver side front marker lamp. Those front marker lamps are an oddity as, with the headlamp switch completely "off", they get their ground via ALL of the rear lamp filaments which combined give a low resistance path to ground which allows them to flash in sync with the main blinker lamps without illuminating the rear lamps. With the headlamp switch in any position except "off" the front markers will flash in opposition to the main blinker lamps because when the mains flash they have +12V from both connections. The front marker lamps are the only alternate path to ground that I can see for the turn signals.

The reasonably expected culprits for improper +12V to the left turn circuit are "TAIL" and "STOP/HAZ". Again, provided that "all four (indicator, main front, front marker and rear) come on steady for left turn but all four both come on and flash for a right" try removing the "TAIL" and "STOP/HAZ" fuses in turn to see if the left side now flashes.