Dash turn signals Options

[Cal]

Question.....when I turn on the turn signals in either direction both indicators on the dash board light up at the same time. Any idea what the problem might be?

[LowBridge]

not sure what year you have but my 75 has a left and right but it's wired as a single indicator. In this post (link) there is a diagram, also I believe I have read on here somewhere how you can split it so they work left and right.

http://www.914world.com/bbs2/index.php?sho...;hl=turn+signal

[orbit398]

Question.....when I turn on the turn signals in either direction both indicators on the dash board light up at the same time. Any idea what the problem might be?

IN my '74, there is a single yellow light in the dash. It comes on when the blinkers are on, either left or right, doesn't matter. Just lets you know the blinkers are on

[toolguy]

You're probably going to find this hard top believe, but check the wattage of the bulbs in all four corners. .
I had this happen when I installed all new bulbs. . After a couple of hours of checking grounds, connectors and circuits, I traced it down to not using the correct wattage bulbs. . Once I put in the old original bulbs the dash indicators worked correctly again.
I never figured out the 'why' of it and chalked it up to the old military electronic explanation that always applies. . "PFM". . Pure F-ing Magic. .

[Dave_Darling]

not sure what year you have but my 75 has a left and right but it's wired as a single indicator.

Your 75 has an earlier tach, then. Only the 70-73 cars (and some early 74s) had silver-cone gauges, which are the ones with left and right blinker indicators.

If the OP has an early 74 car, that's the way it is supposed to be. If he has a mid-74 or later car, his tach has been replaced with an earlier one.

If he has a 70-73 car, then it's time to troubleshoot the turn signal circuit.

--DD

[porschetub]

My 74 did the same thing,not a feature I liked and it may have create issues for me @ vehicle inspection/ compliance time.
McMark came to the rescue recently with info,traced back to the emergency flasher switch and found 2 stray wires,tested them as left and right lamps,connected them and it worked fine.
If you don't have these wires they can be piggybacked to the corresponding ones on the switch,sorry can remember the colours off hand.
Certainly a good safety feature to have IMO.

[Cal]

Thanks for the feedback. I have an early '74 car with the original silver disk gauges.....I'll take a look at the emergency flasher switch.

[Spoke]

You're probably going to find this hard top believe, but check the wattage of the bulbs in all four corners. .
I had this happen when I installed all new bulbs. . After a couple of hours of checking grounds, connectors and circuits, I traced it down to not using the correct wattage bulbs. . Once I put in the old original bulbs the dash indicators worked correctly again.
I never figured out the 'why' of it and chalked it up to the old military electronic explanation that always applies. . "PFM". . Pure F-ing Magic. .

I can take a bit of the PFM out of it for you. See the diagram below with the flasher in the top right corner. Notice the 2nd small coil.

When heavy exterior bulb currents flow when the flasher is flashing, the secondary coil connects the "K" lead to 12V. The K lead is connected to a common wire between the dash indicators.

When the heavy exterior bulb current flows, the K lead connects to 12V, thus one of the dash indicators has 12V across it and lights while the other indicator has 0V across it and is off.

2 scenarios cause both to light:
1) Exterior bulb current is not enough to close the secondary relay; both indicators flash at 1/2 voltage.

2) The secondary coil loses its efficiency over time and heavy exterior bulb current doesn't close the secondary relay.

My flasher suffered from the 2) issue. On the first flash, only the correct indicator lit, then on subsequent flashes, both indicators lit. I solved this by removing the common wire between the indicators from the K lead and attached the common wire to tach ground.

This is a common fix. If you do this fix, you'll find the opposite indicator lights. (RT indicator lights with LT side and visa versa). Swapping the bulbs and bulb holders LT to RT will solve the opposite indicator issue.

[Dave_Darling]

2 scenarios cause both to light:

You forgot one scenario:

Your early 1974 914 has a wiring harness that is only set up to have one turn signal indicator in the tach. It also has a leftover early-style tach with two arrows in it. So the guys at the factory spliced in another section of wire to daisy-chain the two arrows together so both light up at the same time.

I'm pretty sure this is the OP's issue, because he mentioned he had an early 74 car.

--DD

[Cal]

2 scenarios cause both to light:

You forgot one scenario:

Your early 1974 914 has a wiring harness that is only set up to have one turn signal indicator in the tach. It also has a leftover early-style tach with two arrows in it. So the guys at the factory spliced in another section of wire to daisy-chain the two arrows together so both light up at the same time.

I'm pretty sure this is the OP's issue, because he mentioned he had an early 74 car.

--DD

That's interesting.....is that typical? I just assumed something was wrong somewhere. All the exterior indicators and flashers work as they're suppose to. Is there anyone else with an early '74 that can verify if both tach gauge indicators come on at the same time when engaged?

[JeffBowlsby]

Confirmed. I used to have an early 1974 with the silver dot gauges and the turn signal indicators would both blink in unison. Look at the 1974 schematic and actual wiring behind the gauge and you will see why.

The later 1974+ black dot gauges have a single GREEN light by the way...if yours appears yellow, its faded.

[76-914]

You're probably going to find this hard top believe, but check the wattage of the bulbs in all four corners. .
I had this happen when I installed all new bulbs. . After a couple of hours of checking grounds, connectors and circuits, I traced it down to not using the correct wattage bulbs. . Once I put in the old original bulbs the dash indicators worked correctly again.
I never figured out the 'why' of it and chalked it up to the old military electronic explanation that always applies. . "PFM". . Pure F-ing Magic. .

I can take a bit of the PFM out of it for you. See the diagram below with the flasher in the top right corner. Notice the 2nd small coil.

When heavy exterior bulb currents flow when the flasher is flashing, the secondary coil connects the "K" lead to 12V. The K lead is connected to a common wire between the dash indicators.

When the heavy exterior bulb current flows, the K lead connects to 12V, thus one of the dash indicators has 12V across it and lights while the other indicator has 0V across it and is off.

2 scenarios cause both to light:
1) Exterior bulb current is not enough to close the secondary relay; both indicators flash at 1/2 voltage.

2) The secondary coil loses its efficiency over time and heavy exterior bulb current doesn't close the secondary relay.

My flasher suffered from the 2) issue. On the first flash, only the correct indicator lit, then on subsequent flashes, both indicators lit. I solved this by removing the common wire between the indicators from the K lead and attached the common wire to tach ground.

This is a common fix. If you do this fix, you'll find the opposite indicator lights. (RT indicator lights with LT side and visa versa). Swapping the bulbs and bulb holders LT to RT will solve the opposite indicator issue.

Jerry, I hate to ask but one of Murphy's lesser known laws is; "If you make something 100% absolutely clear, you will confuse someone". And I am that someone. So I ask; you pull the BL/BK wire from the indicator lamps between the 2 indicator lamps and attach those to the ground lead on the tach? And why that ground and not any ground? That or circle the spot on your diagram. Sorry for the ignorance. (IMG:style_emoticons/default/beerchug.gif) Kent BTW, love my front turn signals now that everyone can see my turn signals. Also, they are a great "Daytime Collision Avoidance" accessory.

[Cal]

Confirmed. I used to have an early 1974 with the silver dot gauges and the turn signal indicators would both blink in unison. Look at the 1974 schematic and actual wiring behind the gauge and you will see why.

The later 1974+ black dot gauges have a single GREEN light by the way...if yours appears yellow, its faded.

That's great info to know.....thanks.