Tachno needle jumping with turn signal

[timspu]

Gents,

I am hoping there is a simple answer to this issue i am having.
When i have my lights on and a turn signal is working the tacho needle moves in sympathy with the green turn light on the tacho instrument. ( can move full scale)
If the hazard warning light are switched on the needle is stable.
I only get the fluctuations with the combination of turn signal and lights on. Any other combination of heater, lights etc is fine , Engine RPM does not make a difference.

I was thinking i have an alternator issue but i do not understand why the tacho needle does not jump when the hazard lights are switched on. It sounds like the turn signal and hazard lights use the same flasher relay. Do i have a ground issue on the turn signals or is this the Alternator issue. The voltage is a bit low at 13.8 volts at idle.
Just want to eliminate wiring before pulling the alternator out.

Thanks

Tim

[1979-930]

I would start by checking all the grounds for corrosion and cleaning them. The Light is searching for a way to complete the circuit and finding it through the tach.

[timspu]

Thanks for the quick response. Will look at the grounds first. Anyone have any idea where ground studs are. Mine is an 88 Targa, I believe there is a ground stud on the left side of the car adjacent to the suspension tower, would this be the correct one?

[flat6pilot]

There should be ground points local to each turn signal corner. Following the wiring back a little bit, it should reveal a single wire exiting the loom and attached to a blank stud on the body. Like Derrick suggested, they're most likely not making good contact. Simply remove the wire terminal, clean or lightly sand and reconnect. Repeat for all if necessary. It's a common issue. <--- like that pun I used there?

[1979-930]

^^^ Ba-Dump, Crash...

[timspu]

A down to Earth comment!!

Thanks for the advice

Tim

[timspu]

Any reason why this does not happen with the hazards in operation? Same lights flashing but does not cause the issue.

[Rawknees'Turbo]

Originally Posted by timspu

A down to Earth comment!!

Thanks for the advice

Tim

Use caution when saying "down" in the presence of DeezNutzDerrick; he's got that move down pat!!!

[1979-930]

Shhh... I like that to be a surprise.

[Casey at Pelican Parts]

+1 on the ground issue, my bet is you'll find some corrosion in the light housing areas too.

[timspu]

But why does it not happen with hazards on?
Hopefully will dig into it this weekend. Was thinking an issue with ground stud G116. Will also have a look at indicator grounds at the lights themselves.