Dash turn indicators acting up

[TAK65]

Had this problem for long but never paid too much attention as the blinkers work just fine, it's just the green indicators in the instrument cluster acting weird. Hope someone can suggest where to start.
When I have no lights on, everything is normal, the indicators work nice and bright. When parking lights or headlights are on, indicator goes a bit dim and the other direction one starts blinking too, as does the red high beam indicator as well. Outside blinkers still work normally. Occasionally this symptom goes away after driving for a while but not always.
Must be a bad ground somewhere? Anyone had this?

 

[BobW]

Add a ground lead to one of the screws that holds plastic instrument panel cover to the metal panel.

 

[67Dart273]

Add a ground lead to one of the screws that holds plastic instrument panel cover to the metal panel.

^^^THIS^^^

 

[TAK65]

Add a ground lead to one of the screws that holds plastic instrument panel cover to the metal panel.

There already is one, properly connected too. I assume the fault must be somewhere in the parking/driving light circuit as this does not occur when the lights are off.

 

[TAK65]

Another oddity I never noticed before. If I turn on the high beam, both dash turn indicators light up dimly even when not blinking. When I put the arm to the left, the right one in the dash blinks more brightly (left one blinks too, just more dim) and vice versa. Switching off the high beams reverses this. Outside indicators work normally all the time.

 

[67Dart273]

It HAS to be a ground issue. The lights are not connected with the turn signals. The signals power come from the turn signal switch, the lights come from the light switch. The only common connection is the socket ground which is the ground plane of the cluster pc board

The only other possible common source of the problem is the ammeter/ bulkhead connector/ power distro has a drop in that circuit. This should be noticable on other accessories such as heater/ radio/ etc

 

[TAK65]

It HAS to be a ground issue. The lights are not connected with the turn signals. The signals power come from the turn signal switch, the lights come from the light switch. The only common connection is the socket ground which is the ground plane of the cluster pc board

The only other possible common source of the problem is the ammeter/ bulkhead connector/ power distro has a drop in that circuit. This should be noticable on other accessories such as heater/ radio/ etc

I'm no means an electrician but I think can follow the lines in wiring diagram, I do think I'll have to start checking the bulkhead connector as that's the only spot where light/turn signal wires are even close to each other. The dash printed board ground is good.

 

[TAK65]

I think I just made some progress. The problem seems to be the dash ligh dimmer in the headlight switch. Parking lights or driving lights on and dash lights dimmed, the indicators work fine. Brightening the dash lighting brings the problem back. Why? I wish someone would tell me.
Another thing is the high beam indicator, that messes up the dash turn indicators no matter what.

 

[Mike69cuda]

There are at least three grounds on the dash pc board as I recall. They are all grounded by a screw to the cluster pot metal frame. You can have part of the instrument cluster grounded good and part not. I ran into this on mine.

 

[67Dart273]

IT IS a GROUND problem in the cluster.

What happens?

The dash lighting, the turn indicators, and the high beam indicator are all grounded to the cluster ground plane. If it is poorly grounded, turning on other lighting raises the ground plane above ground, and reduces the ground path for (in this case) the indicators.

'I bet" if you were to turn on the high beams and play with the dimmer, you would also see the high beam indicator change brightness

 

[DustyEd]

Years ago, I had "similar" issues with the Duster 340. All I did was remove and clean the headlight switch and the dimmer switch on the floor. If I recall correctly, there's a small release pin you have to push in to remove the headlight switch.

Whatever this info. is worth.

 

[TAK65]

IT IS a GROUND problem in the cluster.

What happens?

The dash lighting, the turn indicators, and the high beam indicator are all grounded to the cluster ground plane. If it is poorly grounded, turning on other lighting raises the ground plane above ground, and reduces the ground path for (in this case) the indicators.

'I bet" if you were to turn on the high beams and play with the dimmer, you would also see the high beam indicator change brightness

Thank you, I just assumed if there is an added ground wire which is tight and good it would not be the grounding issue. Seems like I will have a cluster pulling sunday tomorrow

 

[TAK65]

There are at least three grounds on the dash pc board as I recall. They are all grounded by a screw to the cluster pot metal frame. You can have part of the instrument cluster grounded good and part not. I ran into this on mine.

Three? Well, I have to pull the cluster panel and check them all then.

 

[67Dart273]

Good luck. The shape I'm in I don't envy

 

[TAK65]

Found two screws that ground the circuit to the cluster body. One was properly grounded, the other one not so much. Some rubbing with circuit cleaner and now the ohmmeter beeps on both.
Perfect time to clean the instruments insides too!

 

[67Dart273]

Yup!! Also inspect the board harness connector pins for loose/ corrosion, solder them if they are at all loose. if you can find a "good old" eraser they work well for scrubbing up the contact points where the lamps fit. Also loosen/ tighten the nuts on the gauge studs a couple of times. Those get loose/ oxidized.

 

[TAK65]

Yup!! Also inspect the board harness connector pins for loose/ corrosion, solder them if they are at all loose. if you can find a "good old" eraser they work well for scrubbing up the contact points where the lamps fit. Also loosen/ tighten the nuts on the gauge studs a couple of times. Those get loose/ oxidized.

Thank you very much, got everything back together and working correctly!

 

[67Dart273]

Grounding "of anything" should never have been done through hardware as it was back then. If you've worked on "Much" more modern, most components have dedicated ground wiring, and because of EMI/RFI and ground loops/ other issues with sensitive circuits and sensors, dedicated "single point" ground points are very specific. OEM no longer just "ties something to the body" any old place "no mo"