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914World.com _ 914World Garage _ Both turn signal indicators flash

Posted by: astronomerdave Apr 14 2009, 10:50 AM

When I activate either turn signal, let's say the left one, the left indicator in the tach flashes once alone, brightly for the first blink, then both left & right flash together after that. All four turn signal bulbs (L/R, Front/Back) are OK.

I spent 10 minutes searching on this topic and I found one post that said this is normal, and another post that eluded to it being a problem.

From the outside (where it matters) all seems OK but it's a bit disconcerting to the driver. Is this how it is supposed to be?

Tnx,
Dave

Posted by: silverteener Apr 14 2009, 10:59 AM

Mine blink one at a time. I think both blink if your hazards are on though. Good luck!

Posted by: SirAndy Apr 14 2009, 11:07 AM

QUOTE(astronomerdave @ Apr 14 2009, 09:50 AM) *

When I activate either turn signal, let's say the left one, the left indicator in the tach flashes once alone, brightly for the first blink, then both left & right flash together after that. All four turn signal bulbs (L/R, Front/Back) are OK.

I spent 10 minutes searching on this topic and I found one post that said this is normal, and another post that eluded to it being a problem.

From the outside (where it matters) all seems OK but it's a bit disconcerting to the driver. Is this how it is supposed to be?


Depends on the year of your car.

I don't recall the exact cutoff date, but early cars have the indicators flash individually and later cars have them flash together.
bye1.gif Andy

Posted by: CliffBraun Apr 14 2009, 11:12 AM

QUOTE(astronomerdave @ Apr 14 2009, 09:50 AM) *

When I activate either turn signal, let's say the left one, the left indicator in the tach flashes once alone, brightly for the first blink, then both left & right flash together after that. All four turn signal bulbs (L/R, Front/Back) are OK.

I spent 10 minutes searching on this topic and I found one post that said this is normal, and another post that eluded to it being a problem.

From the outside (where it matters) all seems OK but it's a bit disconcerting to the driver. Is this how it is supposed to be?

Tnx,
Dave


Mine's done this since I bought it, if you care I'm sure you could wire a diode in somewhere and make it go away, but I never have.

Edit: Since I put it together.
Also, every 914 I'm familiar with (three or four) does the same thing.

Posted by: markb Apr 14 2009, 11:19 AM

What year is your car?

Posted by: astronomerdave Apr 14 2009, 11:28 AM

QUOTE(markb @ Apr 14 2009, 10:19 AM) *

What year is your car?


Sorry for omitting that ... it's a 1972

Posted by: astronomerdave Apr 14 2009, 11:31 AM

QUOTE(CliffBraun @ Apr 14 2009, 10:12 AM) *

Mine's done this since I bought it, if you care I'm sure you could wire a diode in somewhere and make it go away, but I never have.


I don't care enough to change it if it's supposed to be that way. I mostly only care if it indicates a problem somewhere (or even if it *thinks* there is a problem somewhere, like a poor connection, for example).

D


Posted by: markb Apr 14 2009, 11:38 AM

You have a wiring problem. Check the wiring diagrams on the Bird Board, especially concerning the diode (?) that's in line for the blinkers.

Posted by: bobhasissues Apr 14 2009, 11:54 AM

Did you change anything, like the flasher relay, or did this just start to happen for no apparent reason? I have found that the Hella replacement relays do not operate the same as the originals which caused that same thing to happen on my car, a '73. I put in a URO aftermarket relay and the flashers work like normal, but the hazards work a little differently.

Posted by: cwpeden Apr 14 2009, 12:11 PM

Mine blink separate.....73 2.0L

Posted by: astronomerdave Apr 14 2009, 12:22 PM

QUOTE(bobhasissues @ Apr 14 2009, 10:54 AM) *

Did you change anything, like the flasher relay, or did this just start to happen for no apparent reason? I have found that the Hella replacement relays do not operate the same as the originals which caused that same thing to happen on my car, a '73. I put in a URO aftermarket relay and the flashers work like normal, but the hazards work a little differently.


I didn't change anything; they have done this as long as I can remember, though I can't say for certain if they did it when I first bought the car.

I never did anything about it before because, as I said, they blink properly (only one side) from the outside. I'm just getting pickier now that I'm close to getting the car drivable again.

Posted by: Scott Schroeder Apr 14 2009, 12:44 PM

My 72 did this when I brough it home 15 years ago. I replaced all of the bulbs, cleaned all of the contacts in the sockets and have not had a problem since.

I have also see cars do this when sitting at a stop light with the lights/fogs/heater (all electrical accessories) on. That was fixed with new ground straps on both the battery and the tranny.

beerchug.gif

Posted by: SirAndy Apr 14 2009, 02:05 PM

QUOTE(astronomerdave @ Apr 14 2009, 11:22 AM) *

I never did anything about it before because, as I said, they blink properly (only one side) from the outside. I'm just getting pickier now that I'm close to getting the car drivable again.

Ok, a '72 should have them blink individually.

Here's one thing to try. Does it do the same when you drive the car above about 3000 rpm?

I had the same problem where they would blink together (albeit dimmer) when the rpms dropped below 3k or at idle. Once i got above 3k rpm, they would blink individually.


I finally traced it to a faulty diode in the circuit. EDIT: Scrap that, wrong diode ...
bye1.gif Andy


It was a ground problem, i remember adding a extra ground wire to the bulbs which fixed the problem ...

Posted by: markb Apr 14 2009, 03:02 PM

Andy, at one time did you mention the type of bulb made a difference? One type for German cars, another for American cars?

Posted by: 904svo Apr 14 2009, 03:31 PM

Point of info, the flasher was design to flash both turn signals if one or more
of the bulbs were burn out. Also if you install the wrong bulbs this will occurs
also. Most people forget the side marks lights are in the circuit also, this can
also cause this problem.

Posted by: SirAndy Apr 14 2009, 03:43 PM

QUOTE(markb @ Apr 14 2009, 02:02 PM) *

Andy, at one time did you mention the type of bulb made a difference? One type for German cars, another for American cars?

Yes. The wattage is different. bulbs sold at your local flaps will most likely not work correctly and can cause all kinds of odd problems ...
shades.gif Andy

Posted by: Spoke Apr 14 2009, 04:36 PM

The 70-72 flasher had some strange connection where the negative side of both indicator lamps are connected together and routed to the flasher. During left/right turn signal operation, this common connection should be grounded inside the flasher.

When this common connection inside the flasher fails, both indicators flash at the same time at a reduced intensity.

My 71 did this when I bought it. My solution was to remove this negative connection from the flasher and connect the negative sides of the flashers to ground. This is very easy to do since there are several ground points on the back of the tach.

For the later cars (73-76), they use a single indicator for left/right turn signals.

Posted by: markb Apr 14 2009, 04:45 PM

QUOTE(SirAndy @ Apr 14 2009, 02:43 PM) *

QUOTE(markb @ Apr 14 2009, 02:02 PM) *

Andy, at one time did you mention the type of bulb made a difference? One type for German cars, another for American cars?

Yes. The wattage is different. bulbs sold at your local flaps will most likely not work correctly and can cause all kinds of odd problems ...
shades.gif Andy

OK, so which is which?

Posted by: Slick914 Apr 14 2009, 08:25 PM

My 73 does the exact same thing. The indicator will flash once normally then both flash together after that.

Andy... Did you add that extra ground to the dash indicator?

I'll have to check all the exterior bulbs as well to make sure they're the correct wattage.


Posted by: SGB Apr 14 2009, 09:45 PM

Its the flasher unit. Mine did that FOREVER until a friend at a VW shop pulled his old 72 out to start fixing up. His also did the "both arrows flashing" thing, and he replaced the flasher with a vw bus flasher. I dunno the year- may not matter- but it fixed his so I bought one and it fixed mine too. I was amazed. I had watched both arrows blink for 17 or 18 years. If I have to, I can get a part number. I think just look at cip1

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