Indicator/Flasher Relay

[10DJM]

The indicators in my 1973 911E Targa suddenly stopped working.
I have now sourced and trialed two new and apparently correct part numbered (91461830311) relays but on both occasions they operate appropriately apart from flashing both dash indicator direction lights constantly on turning on the ignition. Any thoughts?

[hot66]

Are the indicator lights in the dash flashing when the handbrake is off ? I tried a new relay recently and teh dash bulbs both flashed without the indicators on but instead in time with the handbrake warning light when the handbrake was on

[10DJM]

Problem resolved if not solved.
I remembered I'd recently had the tachometer out and had a bit of difficulty reseating it ... so I thought I'd take it out again and hey presto the indicators
started working appropriately. Reseated it and all is well.
Must have been stretched wires/earth etc.
Will now leave well alone.

[911hillclimber]

My 73T indicator lights in the tachometer have always flashed simultaneously when indicating left or right.
Bob Watsonville said it was an earth ‘thing’.
Never sorted it despite trying…

[aircooled]

I have the same problem. I was told that the modern relays just do this. There is no fix apparently.

[SeanP]

I have the same problem. I was told that the modern relays just do this. There is no fix apparently.

There is!
The original flasher relays to the tell tail lamps switches the ground, there is a 12V permanent live to the other side of the lamp, if i remember rightly its a blue wire.
The new flasher switches a 12V signal out to the tell tail lamp, but the lamp already has 12V on it and is connected to the other lamp by the original 12V feed. The current looks for a path to ground and lights both lamps whilst going to ground.

Take off the blue wire with its piggy back to the tell tail lamps in the tach
Make it safe as it has 12V on it permanently!
Make a new wire to go onto the tell tail lamps in place of the blue wire and connect it to a ground point on the body of the car.

[911hillclimber]

Interesting.
When I'm in the mood for a delve into the dash I'll try that.
I have mine 'rigged' such that one green light flashes for left or right, just so I spot the indicators are still switched and cancel it.

[misteralz]

In my day we had one telltale for indicators and that was that!

Yes, I am aware I'm the youngest person here. But mk1 Fiestas and mk2 Golfs only had the one wee green lamp to let you know.

[911hillclimber]

I'm of that 'keep it simple' generation and the one is enough.
"your indicator is on, reset it or leave it as you are stating your change of direction"
Nice and simple.

[aircooled]

I have the same problem. I was told that the modern relays just do this. There is no fix apparently.

There is!
The original flasher relays to the tell tail lamps switches the ground, there is a 12V permanent live to the other side of the lamp, if i remember rightly its a blue wire.
The new flasher switches a 12V signal out to the tell tail lamp, but the lamp already has 12V on it and is connected to the other lamp by the original 12V feed. The current looks for a path to ground and lights both lamps whilst going to ground.

Take off the blue wire with its piggy back to the tell tail lamps in the tach
Make it safe as it has 12V on it permanently!
Make a new wire to go onto the tell tail lamps in place of the blue wire and connect it to a ground point on the body of the car.

Good info! Neither of my tell tale lights work either, the green side light lamp or the high beam light so this makes sense.

Do you have any photos or an idiots guide it doing this as I’d love to get it all working properly again? To be honest I find your instructions above a bit hard to follow. But I am perhaps being a bit thick.

[SeanP]

Just had a look at a wiring diagram I have to hand (1969 911). But they are all essentially the same circuit.
This is a pretty simple circuit, but has inbuilt flaws where if there is a bad ground can cause the voltage to back feed and cause both tell tail lamps to flash when operating the indicators. The mod below is also essential when upgrading to LED indicators with the corresponding flasher unit.

The 12V supply to the tell tails is blue with a white stripe and goes to both lights on the tach from the flasher unit base.
Left tell tail is black with a white stripe. This wire goes to the hazard warning light for information
Right tell tail is black with a green stripe . This wire goes to the hazard warning light for information.

You will need a length of brown wire to make a new earth strap for the tell tail lights. You can do this for each tell tail light individually or loop them through.
2No. Standard (6.3mm) female spade connectors
1No. Or 2No. 8mm ring lug connector.
Crimping tool
13mm spanner

Remove the tachometer from the dash
You will see the left and right tell tail lamps at the top of the tach.wire colours identified above.
Disconnect the blue and white wire from the tell tail build holders and make sure that it is isolated. (Tape it up so that it cannot touch any metal as it is still live).
In place of the blue and white wire make up a new length of wire (brown) and connect it to both tell tail bulb holders and to a ground point on the car body. There is a 8mm bolt ground point on the body of the car near the LHS inner wing/bulkhead.

Test the indicators and marvel at your electrical prowess.

This solution works for LED tell tail bulbs and/or solid state flasher units where if you install LED lamps in the tell tail lights and you operate the indicators you get both sides of the indicators working at the same time! It also removes the issues with bad ground points where both tell tail lights work at the same time when operating the indicators. It will not fix non operative and defective lamps due to bad ground points or blown lamps.
Most times when both tell tail lamps are operating at the same time when using the indicators there is a ground fault at one of the indicator boxes causing voltage to back feed through the flasher relay and through the path of least resistance.

[hot66]

Continuing this subject…

So my original relay has started going mental and with the handbrake on, it was flashing the warning light at strobe light levels of speed .. and also the indicators too… this has been getting worse over recent months.

So fitted the new ‘correct’ relay I bought and fitted it .. indicators back to normal speed, but as mentioned previously, with the handbrake on the warning light flashes but so do both indicator tell tale lights on the dash at the same time.

Now my car is Italian spec and does Not have hazard lights. Would it be possible these new relays are ROW spec and my cars original with no hazards is a different spec ?

Can original relays be overhauled ?

[Ian Comerford]

If your thinking is correct then surely the Italian classic Porsche market is the place to look for the relay James? There’s a guy on IB who might help (runnersp)

[jb]

When we were on the coast to coast my indicators also stopped working properly. I don’t remember what they did however Barry took the relay apart and fixed it so perhaps you can do so too.

[SeanP]

Check your grounds!
The thing that is common to all of these circuits is the grounds.
Electricity like water will follow the path of least resistance. The reason everything is going haywire and flashing is there is a bad ground (high resistance) and it is finding the path of least resistance.