Turn Signals on Tach Blick Together

[arbita1]

My turn signals on my tachometer used to work correctly. Then one day they started blicking together regardless of the turn signal stalk position. The exterior signal lights all function correctly.

My first thought was that the ground for these lights may have become disconnected. I checked the back of the tachometer and everything is hooked up properly. Supposedly there is a main ground located somewhere behind the vent controls in the cabin that is tied to the signals. I figured I'd start there. I looked under there yesterday but couldn't locate it.

Does anyone know where this ground is? Does anyone have any other ideas?

[bluesky]

In my 73, the turn indicators in the dash blink together either when:

1) I have a bulb on the outside not lighting correctly (burned out or not seated in the socket correctly)

2) The alternator is not producing enough "juice" to power everything....this especially happens when I have the H4's and the stereo on and I'm sitting at a traffic light at idle.

In your case, have you checked your external bulbs to make sure they are working and have you checked your alternator/belt?

Do they stop blinking together if you increase rpm's?

[arbita1]

Originally Posted by bluesky

In my 73, the turn indicators in the dash blink together either when:

1) I have a bulb on the outside not lighting correctly (burned out or not seated in the socket correctly)

2) The alternator is not producing enough "juice" to power everything....this especially happens when I have the H4's and the stereo on and I'm sitting at a traffic light at idle.

In your case, have you checked your external bulbs to make sure they are working and have you checked your alternator/belt?

Do they stop blinking together if you increase rpm's?

1. Yes...all outside bulbs are working properly. (But now I'm second guessing myself. I'll confirm that tonight.)

2. My alternator belt is tight. I do not get the alternator light on at all. I don't have any other electrical issues. And the battery stays charged.

3. No...RPM doesn't seem to be a factor. It is constant regardless of what RPM I am at.

[bluesky]

If everything checks out with the bulbs, then I wonder if it is your turn signal stalk switch failing or needs the contacts cleaned.

[arbita1]

Originally Posted by bluesky

If everything checks out with the bulbs, then I wonder if it is your turn signal stalk switch failing or needs the contacts cleaned.

I thought of that, but then I thought why would the exterior signals work correctly and not the interior. I don't think there are two sets of contacts on the switch.

[rusnak]

maybe the turn signal relay then?

[moliver]

I have the same issue on my 75, something is just weird with those signal arrows.

I replaced the signal switch and cleaned all the contacts for the bulbs etc.

Seems to be more of an intermittant problem on mine. Does the headlight switch dim the blinker lights? Wonder if something is going on there?

Mike

[rusnak]

I *think* but could be wrong that the only common links are the turn signal swich and the turn signal relay. I admit I'm at work buried to my eyeballs with work, and do not have time or access a wiring diagram. But I vaguely recall looking at this a long time ago.

[john walker's workshop]

relay. get a hella, not a schucks.

[dshepp806]

Originally Posted by john walker's workshop

relay. get a hella, not a schucks.

I long for these types of responses from the P-wrenches.......I swear, it's like a good western........The Master editor,..minimal words,..succinct by definition....no frikin' science,..just raw trenchwork...the best.

.....and you'd damned well check out his recco's!!

Best,

Doyle

[tmctguer]

i had a similar problem on my 73E and created a post.......just can't find it at the moment ! here's what i did to resolve my situation;

1). in spite of removing them, and burnishing both the bulb sockets and the brass connections that touch the back of the bulbs, i could not get the dual flashing to stop.

2). I also found that the small rearward bulb on the driver's side turn signal was not illuminating. i replaced the bulb and it still did not work.

3). after getting feedback from Pelican and Early S Registry members, i added a new ground wire to both front turn signal housings.

it wasn't until i finished item #3 that the dual flashing issue stopped.

curiously, the small bulb STILL does not illuminate. but the irritating flashing has stopped. if I find the link of my posting, I'll attach it later.

[arbita1]

I've verified all my exterior signals are working properly.

As John said, I've been leaning toward the relay being the problem. However I would like to verify that the ground connection is in fact good first before I start spending money.

Can anyone point out where the ground is in the cabin behind the vent controls? A picture would be great! I couldn't find it in the 2 minutes I had to look.

[Rich Lambert]

Originally Posted by tmctguer

3). after getting feedback from Pelican and Early S Registry members, i added a new ground wire to both front turn signal housings.

it wasn't until i finished item #3 that the dual flashing issue stopped.

I had the same problem and came up with the same solution. It has to be something in one of the relays.

[ossiblue]

Check the ground wires at the signal housings--especially the rear housings where the ground wire is secured underneath the bumper. This is often disconnected or at least extremely dirty. Not sure of the front assemblies, but it is relatively easy on a 73 to clean up the ground contacts on all assemblies, plus it's free. If that doesn't work, then try the relay, as noted.

[kucharskimb]

I run into this problem on my 72 every so often. What my issue came down to was the side bulb behind the reflector/diffuser plate. When inserted into the socket, twisted and locked, both bulb contacts touch one of the socket contacts. I could back off the bulb a little bit, and it would be normal for a couple weeks, then vibrate back into the fully seated position and self-ground.

The solution was to bend the socket contacts apart a little to prevent cross contact. You can check this my putting two small dots on the glass part of the bulb that line up with the contacts. Use the dots for orientation when the bulb is fully seated and compare the orientation to the socket contacts.

Hopefully, it is just a relay...

[moliver]

Problem...both signal lights above the tach were always illuminated. Most of the time the correct signal light above the tach would flash like it should, but not always.

Solution: Relay replacement.

Just wanted to give some feedback as to what I had going on and what solved the problem.

Relay was a ***** to get to, but once swapped life was good once again.

Thanks for all the help.

[dshepp806]

Anyway you can dissect the bad one and have a look-see inside?

Congrats on the fix...

Best,

Doyle

[Porsche_monkey]

And confirm you bulb wattage is correct, not too low. That won't cause this issue, but in conjunction with a failed indicator switch it will.

[Rich Lambert]

So, which relay was it?

[moliver]

Was the blinker relay...on my 75 its up behind the firewall behind the gauges.

NEW PROBLEM

Now the indicators above the tach blink the opposite of what they should. The worked correctly when I replaced the relay...now they are back to their old tricks again.

Is there a connection that could be crossed?

Anyone run into this issue?