Fast-blinking left turn signal, but all bulbs/filaments are working?

[jawn101]

So I know the fast blink usually indicates a bad bulb. But my bulbs all seem to work. Both filaments in the 1157 up front are ok. If I turn on the parking lights, the dim filament glows. If I hit the hazard switch, all 4 markers flash in sync and at the right speed. If I signal right, all is well. If I signal left, the blink is double-time and the front signal appears 'out of sync'.

I swapped the front right 1157 bulb to the left hand side and vice versa, and now if I signal left or right I get the rapid flash on either side. I also noticed that if I hit the hazard switch with the lights off, the hazard and headlight switch lamps (in the HVAC panel) flash in time with the blinkers. They don't do that normally. Are they supposed to?

The 1157s seem to only fit into the socket one way on account of the different heights of the side nubs, so they shouldn't be backwards in the sockets....

What the heck?

[Ron]

Swap them back and if it goes back to the right side only flashing fast, assume there was something wrong with one bulb and buy two...then go on to the other problems.

[jawn101]

Swap them back and if it goes back to the right side only flashing fast, assume it was a bulb and buy two.

Fair enough, I was planning to do that anyway. What about the lights in the LMS and hazard switch, are those supposed to flash? They never did that before but it's pretty cool.

[Ron]

My hazards make all four turn signals and their indicators flash only.

If one filament on a 1157 burns and drops across the other one, weird things happen depending on which end, of which element it was, the car, the position, mods, etc. I don't know if one could feed power to the switches like that right off. You might try removing both and see if the switch lights come on at all... But I would definitely do the swap back test since it would prove the bulbs...and a bad one will screw up any trouble shooting on the other...

[jawn101]

Alright. I will get some 1157s and 1156s tomorrow just in case the ones in back are acting up. Will report back. The flashing switch lamp symptom is so weird.

[john 05141]

I had the same thing. In my case all bulbs and sockets were fine too. But the strange thing was sometimes it would work fine, some times, it would double the speed. Especially while driving this would happen.
The problem was that the socket on the left front blinker was slightly too large. So when bending the socket inwards a bit so the bulp was more snug, solved the problem in my case.

John

[jawn101]

I had the same thing. In my case all bulbs and sockets were fine too. But the strange thing was sometimes it would work fine, some times, it would double the speed. Especially while driving this would happen.
The problem was that the socket on the left front blinker was slightly too large. So when bending the socket inwards a bit so the bulp was more snug, solved the problem in my case.

John

Very interesting, I'll check that out too. Thanks for the tip.

PS - did you have the flashing lights in your switches too? I've been racking my brains with the wiring diagram to figure out how that could have happened.

[Ron]

I've been racking my brains with the wiring diagram to figure out how that could have happened.
From a quick look: Maybe #71 D.I Switch => #11 Front D.I. filament => #11 Front Park filament => through fuse #2 => Fuse #5 junction => #70 main light switch

[jawn101]

From a quick look: Maybe #71 D.I Switch => #11 Front D.I. filament => #11 Front Park filament => through fuse #2 => Fuse #5 junction => #70 main light switch

But the switch lights don't blink with the DI's, only with the hazards (all 4 at once when hazard switch is engaged)

[Ron]

Sorry, should of re-read since last night.

#72 => #12 filiment 1 => #12 filiment 2 => #24 => #70? (could be other side as well)

Did ya pull both, check, then swap and check?

[DMC5180]

Do you have your lights configured to flash the markers? What is the condition of the sockets? Have you checked the rear signals?

[jawn101]

Do you have your lights configured to flash the markers? What is the condition of the sockets? Have you checked the rear signals?

Nope, stock config. Sockets are fine. Rear signals are fine.

Actually, the sockets weren't all 100%. John from Belgium wins this one, the front left socket was slightly misshapen and had some nasty old bulb grease in it. I cleaned it all out with electrical cleaner and reshaped the outer surface slightly - et voila. Everything is back to normal. I did put new bulbs in the front lights since I had them apart anyway.

[john 05141]

Glad to be of service! That is what I love about this forum, (sometimes) easy to find someone who solved a problem.
I also notived the sockets were a bit rusty, so I used a dremel with a brush to clean the inner socket out completely.

John

[Ron]

Cool beans!
(But I'd guess you either disturbed a shorted filament working on it or didn't try a set of bulbs since you never said.)

FWIW- A loose connection can cause the symptoms John was having. But as screwy as the stock delorean's wiring is, a loose/dirty connection at the bulb socket can not cause the main light switch bulb to flash with the hazards. Think about it...a bad connection would cause the bulb to be dim, or, be exactly the same same as if a filament burnt out, and we would have been hearing about this a lot before now, me thinks ;-)

[jawn101]

Cool beans!
(But I'd guess you either disturbed a shorted filament working on it or didn't try a set of bulbs since you never said.)

FWIW- A loose connection can cause the symptoms John was having. But as screwy as the stock delorean's wiring is, a loose/dirty connection at the bulb socket can not cause the main light switch bulb to flash with the hazards. Think about it...a bad connection would cause the bulb to be dim, or, be exactly the same same as if a filament burnt out, and we would have been hearing about this a lot before now, me thinks ;-)

Ron - I did try the new bulbs in the sockets before I reshaped the left hand one. The symptoms persisted. I also replaced the rear flashers with new 1156 bulbs just to be sure - no difference there either! I have no idea why the LMS and hazard switches were blinking. Is the hazard (three triangles) switch supposed to? Or just the green directional arrows in the binnacle?

[Ron]

Ron - I did try the new bulbs in the sockets before I reshaped the left hand one. The symptoms persisted. I also replaced the rear flashers with new 1156 bulbs just to be sure - no difference there either! I have no idea why the LMS and hazard switches were blinking. Is the hazard (three triangles) switch supposed to? Or just the green directional arrows in the binnacle?
Now I see the problem -- You have the three triangle version in stead of the two like mine...:deviltail: J/K!

Seriously, that be the case, you must have had a short in the socket itself. There are only 3 wires. Loose or open on any or all 3, you loose a light, or two, if one of them is the ground. Short one or both of the others to the ground, you blow a fuse. The two non-grounds shorted together is all that is left AND the only way to short the two circuits ( and could possibly make the LMS light flash with the hazards (eg filaments shorted, HEAVY conductive corrosion/contamination across bulb contacts,...). If a REAL sloppy fit, the bulb contacts could short the non-ground connectors together too, but you indicated the pins were catching. IDK, but I bet if you check your old socket, you will find the non-ground wires are shorted together...whatever it was, now that it is removed, a couple of quick checks with a meter should tell the whole story...

Mine never blinks and I'm not screwing with it until I'm in there since it would be useless really....but yours obviously has a bulb, I can't think of what else it could be for.....Now, I do remember Bill saying you could swap them with the LMS and there is no mention of it in the manual's description or the schematic...so someone else will have tell us both....
This is why I like to get to the bottom of things...learn something new every day!

[pt11334]

I have the same problem. All four turn signals flash really fast, but the front ones they seem very dim when they do. You can also see the Ac panel light flash at the same time as the turn signals. :frantic:

[Shep]

I have the same problem. All four turn signals flash really fast, but the front ones they seem very dim when they do. You can also see the Ac panel light flash at the same time as the turn signals. :frantic:Not sure if you saw this post, but Post #6 (http://dmctalk.org/showthread.php?4729-Fast-blinking-left-turn-signal-but-all-bulbs-filaments-are-working&p=67110&viewfull=1#post67110) is the root cause of Jon's problem. Considering you say the front bulbs seem dim in flashing, this would be my guess as to what the issue was. Give it a try, and let us know if it works! :)

While you're in there, you might want to use a wire brush to clean all the rust off the connectors. That could be a contributing factor as well.

[Ron]

If everything works but at the wrong speed/brilliance (ie no one bulb acting different than its mate on the other side or end of the car), the odds are that you have the wrong flasher, wrong bulbs (but match each other), or you have a bad connection that feeds/grounds the set (ie not a bad connection for a given bulb).

[DMC5180]

I have the same problem. All four turn signals flash really fast, but the front ones they seem very dim when they do. You can also see the Ac panel light flash at the same time as the turn signals. :frantic:

You live in Miami near Salt Air environment and its a car with 31 year old electrical components and light sockets. Corrosion is the likely culprit. Pull all bulbs from the sockets and clean. The front bulbs a famous for corroding. They are dual filament 1157 front bulbs and can cross/back feed the park light side of the system (includes A/C panel lights) causing all sorts of weird lighting issues.

Here is an example of my "Amazingly still working" Front side marker bulb and socket the bulb is stuck in place but still works for now. It's on my list to be replaced one of these days.

15463

[jawn101]

You live in Miami near Salt Air environment and its a car with 31 year old electrical components and light sockets. Corrosion is the likely culprit. Pull all bulbs from the sockets and clean. The front bulbs a famous for corroding. They are dual filament 1157 front bulbs and can cross/back feed the park light side of the system (includes A/C panel lights) causing all sorts of weird lighting issues.

Here is an example of my "Amazingly still working" Front side marker bulb and socket the bulb is stuck in place but still works for now. It's on my list to be replaced one of these days.

15463

Yep, this is what my problem ended up being - weird corrosion patterns that was likely caused by the ancient bulb grease in the socket. Cleaned everything up real good and slightly re-shaped the socket to make better contact and all was right.

[pt11334]

Thank you so much for you help. Problem fixed. I ended up cleaning all the sockets. Got rid off all the corrosion and the old light bulbs. Replaced all bulbs with new sylvania and the blinkers are back to normal.