Weird problem with Euro front turn signal/running lights

[EddyM]

I’ve got a weird electrical problem. The car (1973) has front Euro turn signal/marker lights with the funky Euro bulbs that have two wires coming out of the bulb itself. The wires (one white, one black) are plugged into corresponding white and black wires coming into the light mounting recess from below. There doesn’t appear to be a brown grounding wire, from which I deduce that all switches involved are grounding switches. The bulbs on both sides have two filaments.

The passenger-side light has always worked correctly – that is, when I turn on the running or headlights, the dimmer of the two filaments lights up. When I use the turn signal to indicate a right-hand turn, the bright filament flashes, I can hear the flasher unit under the dash, the rear turn signal light flashes, and the green indicator light in the combination instrument (gas/coolant temp) flashes in synch with everything. The driver’s side is a different story, and that’s where my problem is. When I got the car, turning on either the running or headlights would cause the brighter of the two filaments to light up. Using the turn signal to indicate a left-hand turn would make the rear signal light blink, I could hear the flasher unit under the dash, and the green indicator light would flash. However, because the bright filament in the front light was already lit up, there was no flashing signal from that light. The flashing rate was the same for both sides.

Figuring there was a chance the light had been wired incorrectly, I pulled it. I found the white wire from the light plugged into the black wire from the body and vice versa. So I swapped them around and now the driver’s side front light is wired the same as the light on the other side (which I checked). It was a simple fix for the turn signal/running light issue, but it caused another problem. Turning on the running or headlights does, in fact, now turn on the dimmer of the two filaments in the driver's side light. Using the turn signal to indicate a left-hand turn does, in fact, cause the brighter of the two filaments to flash (the rear turn signal light also flashes, as it had done previously), and I can hear the flasher unit under the dash. However, the green indicator light in the combination instrument now flashes just once at the start and that’s it – it does not continue to flash regularly in synch with the front and rear bulbs and/or the flasher unit, as it does when signalling with the passenger-side light. In addition, the turn signal flash rate for the driver’s side light is now about half as fast as that for the passenger side (which has not changed from how it operated previously).

I’m no electrical genius so I have no idea why what I did solved one problem and created another. It’s probably something incredibly simple that I’m overlooking (I did make sure the connections were solid) and I can’t find anything on turn signals where someone has had a similar issue. Does anyone have any ideas what’s going on here? Or, is this the car’s way of telling me I need to convert the units to regular American twin-filament bulbs? (I do have a printed copy of the post I found showing how to do that).

[roadhog0]

I believe you need to adjust and clean your blinker relay or replace it.

[EddyM]

I believe you need to adjust and clean your blinker relay or replace it.

Didn't know they could be adjusted - thought they were an "either it works right or it gets replaced" item.

Will pull it in the next couple of days and take a look - can you explain why it provided correct operation when the wires were reversed on the one front turn signal light and now has a problem when those wires are correctly connected?

[c.d.iesel]

try new bulbs on the left side

matching what's on the right side

[vinntagejoe]

Damn that was a long lead in............good luck with that.

[EddyM]

Yep, it was a long lead in, but I have always figured that when dealing with an electrical problem there's no such thing as too much information.

Changing the bulbs would be a problem with the front ones - where in the world can you find those silly things? That's why I'm strongly considering re-plumbing the guts of each light unit to accept standard American auto bulbs.

Earlier today I had enough time to root under the dash, extract the flasher unit, and examine it. Although it didn't appear to have any dirt or corrosion on the terminals, I rubbed them with some 200-grit paper and used some computer canned air to blow away any residue. I also pulled the driver's side front light and double-checked the connections. Once re-assembled, I tested and everything now works like it should. Whatever gremlin was present has, at least for the time being, gone to haunt someone else.

Thanks for the suggestions.

[roadhog0]

I'm no expert but I believe cleaning and adjusting the blinker unit has helps with resistance or something. Someone on here knows, I just know I've heard that it sometimes solves the problem so I like to offer the suggestion. Good thing it's fixed now though!!