Dash light problem

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russhal

russhal

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I have a 71 swinger. About 2 months ago, when driving at night, the dash lights quit working with headlights on. The dash lights work fine with just the running lights on. I replaced the headlight switch. Still have the same problem. Everything works, running lights, dome light, no dash lights with headlights on. 2 years ago, I went to a 1 wire alternator. Factory wiring is untouched in the car. Where should I start?
 
I assume you have you run the dash dimmer from 0 to full and back a few times? (don't think it is the issue but you never know)
 
And if that's not it check your fuses, and the test at the plug on the back of your cluster for power at that pin.
If no power there, work back towards your headlight switch.
You may also need a ground from the cluster to the car metal.
 
Dana67Dart said:
I assume you have you run the dash dimmer from 0 to full and back a few times? (don't think it is the issue but you never know)
Click to expand...
I have. Reostat works fine with headlight switch in position 1 but in position 2 with headlights and running lights, dash lights go out
 
Was there any rewiring of the connector to the headlight switch? Under dash?

Checked the fuses?

Some times I ask obvious questions... Reason... I worked in Facility Operations field and had an employee call and say their PC would not power up. I asked if the PC was plugged in. The answer was that the power-strip had been unplugged for some reason but still did not work after plugging the power strip back in. I went to check it out and found the employee had plugged the power-strip into itself. I plugged the power-strip into the wall and all was right in the world. Sometimes it is the simplest of reasons for a failure
 
The electrical routing for these is wild!
The headlight have nothing to do with the dash lights, two different circuits, coincidentally activated. When you pull out the headlight switch, a wire becomes energized and goes back to the fuse box. The wire on the other side of that fuse goes back to the dash and handles several things in the gage cluster. There could be a short that is pulling down the voltage. Try disconnecting the wiring harness that goes to the rear and see if there is still an issue. You could do the same with the steering column plug.

I've been chasing a similar issue and have noted a voltage drop as soon as I plug in the gage cluster...still struggling, so my advise might be worth what you paid for it
 
Dana67Dart said:
Was there any rewiring of the connector to the headlight switch? Under dash?

Checked the fuses?

Some times I ask obvious questions... Reason... I worked in Facility Operations field and had an employee call and say their PC would not power up. I asked if the PC was plugged in. The answer was that the power-strip had been unplugged for some reason but still did not work after plugging the power strip back in. I went to check it out and found the employee had plugged the power-strip into itself. I plugged the power-strip into the wall and all was right in the world. Sometimes it is the simplest of reasons for a failure
Click to expand...
Yes checked the fuses but you're right. Generally it's the simplest solution that works
 
Michael Brisebois said:
The electrical routing for these is wild!
The headlight have nothing to do with the dash lights, two different circuits, coincidentally activated. When you pull out the headlight switch, a wire becomes energized and goes back to the fuse box. The wire on the other side of that fuse goes back to the dash and handles several things in the gage cluster. There could be a short that is pulling down the voltage. Try disconnecting the wiring harness that goes to the rear and see if there is still an issue. You could do the same with the steering column plug.

I've been chasing a similar issue and have noted a voltage drop as soon as I plug in the gage cluster...still struggling, so my advise might be worth what you paid for it
Click to expand...
That's good to know. Strange how it works fine until the headlights are on. I was hoping to find something simple. They call it chasing wires for a reason. Stuff like this makes you feel like you're chasing something you can't catch!
 
Michael Brisebois said:
The electrical routing for these is wild!
The headlight have nothing to do with the dash lights, two different circuits, coincidentally activated. When you pull out the headlight switch, a wire becomes energized and goes back to the fuse box. The wire on the other side of that fuse goes back to the dash and handles several things in the gage cluster. There could be a short that is pulling down the voltage. Try disconnecting the wiring harness that goes to the rear and see if there is still an issue. You could do the same with the steering column plug.

I've been chasing a similar issue and have noted a voltage drop as soon as I plug in the gage cluster...still struggling, so my advise might be worth what you paid for it
Click to expand...

NOT QUITE CORRECT here is how the dash dimmer circuit works......

Dimmer gets voltage from the TAIL LAMP circuit so that fuse must be good and that circuit working

Through the dimmer, out to the fuse panel on TAN to the dedicated "inst" fuse. THIS FUSE DOES NOTHING ELSE except supply power to the dash lights which are all orange wires.

No idea why the headlights might be affecting this.
 
I suppose there could be a voltage drop, headlights drawing so much that although the dash lights are still on, they're so dim that you cant see them on. A better guess is a faulty headlight switch. Is it dropping park lamps also at headlights on?
 
RedFish said:
I suppose there could be a voltage drop, headlights drawing so much that although the dash lights are still on, they're so dim that you cant see them on. A better guess is a faulty headlight switch. Is it dropping park lamps also at headlights on?
Click to expand...
The only time the dash lights don't is with headlights on. I do think I'm on to what's causing the problem. I tinkered with it before work this morning and noticed something I missed. With parking lights, dash lights work but the turn signal lights are on too. The get brighter and dimmer with the reostat adjustment. Turn the headlights on and dashlights go out turn signals are lit up and respond to reostat adjustment. I was working the heater control panel about week before noticing the problem. The radio light is on the same circuit as the dash light and looks like turn signal/emergency flasher come off the same feed at the firewall. I think something is grounded out where the factory radio was and probably did it. The factory radio plugs should be dangling. Not sure if any of this makes since but following the wiring diagram it goes from switch to dash lights, to fuse box but breaks off to radio light to turn signal/ emergency lights. I think I'm right?
 
russhal said:
The only time the dash lights don't is with headlights on. I do think I'm on to what's causing the problem. I tinkered with it before work this morning and noticed something I missed. With parking lights, dash lights work but the turn signal lights are on too. The get brighter and dimmer with the reostat adjustment. Turn the headlights on and dashlights go out turn signals are lit up and respond to reostat adjustment. I was working the heater control panel about week before noticing the problem. The radio light is on the same circuit as the dash light and looks like turn signal/emergency flasher come off the same feed at the firewall. I think something is grounded out where the factory radio was and probably did it. The factory radio plugs should be dangling. Not sure if any of this makes since but following the wiring diagram it goes from switch to dash lights, to fuse box but breaks off to radio light to turn signal/ emergency lights. I think I'm right?
Click to expand...
I just dont know. Let us know what you find.
 
I know this is not the solution but...on my 67 dart you can press the brake, turn on the flashers and listen to the radio all without the key in the ignition. In the shop manual it even says that a back feed condition can result under certain conditions. My point is that if you are getting power form one cir applied to another cir (by way of open grounds or shorted wires or a back-feed like the one I described) maybe you are zeroing out the voltage or the like

I cant wait till you find the answer and report back.
 
russhal said:
The only time the dash lights don't is with headlights on. I do think I'm on to what's causing the problem. I tinkered with it before work this morning and noticed something I missed. With parking lights, dash lights work but the turn signal lights are on too. The get brighter and dimmer with the reostat adjustment. T
Click to expand...

I almost mentioned this. CHECK YOUR CLUSTER GROUND., Most people, including me, recommend an added ground pigtail from a ground point on the cluster group to the dash frame or column support
 
crackedback said:
Check your grounds from the instrument cluster.
Click to expand...
Chased wires in the dash and could find nothing I could say was the problem. I went to the headlight switch, which I replaced. It looks the same as the old one but has a little grounding tab on the back that I didn't think was nessary. Well.....I grounded it to the dash. So it must be nessary. Dash lights remain on with headlights. So now I'm looking at all the lights on the car. Everything looks good except for the turn signal lights aren't working right. They just come on and stay on. They do work in emergency and flash. I'll make sure the bulbs are correct but if they are, next step would be the steering column. Thanks for all the help guys. I really hate playing with wires.
 
russhal said:
Chased wires in the dash and could find nothing I could say was the problem. I went to the headlight switch, which I replaced. It looks the same as the old one but has a little grounding tab on the back that I didn't think was nessary. Well.....I grounded it to the dash. So it must be nessary. Dash lights remain on with headlights. So now I'm looking at all the lights on the car. Everything looks good except for the turn signal lights aren't working right. They just come on and stay on. They do work in emergency and flash. I'll make sure the bulbs are correct but if they are, next step would be the steering column. Thanks for all the help guys. I really hate playing with wires.
Click to expand...
OK "turn signal lights stay on" isn't clear. Which lights? anyway... when the turn indicators in the dash come on with the park lamps there is a loss of chassis ground at front park/turn fixtures. Park lamp current finds a ground through the turn circuit instead of through the bulbs base and fixture. Rear lamps can't back feed in this manner since the path is interrupted at turn signal switch for brake lamp operation.
So if the turn indicators in the dash are the issue, check ground wire connections at radiator support.
 
Question... If you put the turn signal switch as if you were to turn left or right do the proper lights light up inside and out but not flash? If that is the case I would say blinker mechanism. On my 67 dart There are two units one for blinkers and one for E flasher. I suspect yours has two also.
 
russhal said:
Chased wires in the dash .
Click to expand...
You are not listening. CHECK THE CLUSTER GROUND

It is not a wire. To repeat ADD a pigtail from the cluster ground point and bolt it to the dash frame/ column support. The cluster ONLY GROUNDS (originally) through the mounting screws.
 
W
67Dart273 said:
You are not listening. CHECK THE CLUSTER GROUND

It is not a wire. To repeat ADD a pigtail from the cluster ground point and bolt it to the dash frame/ column support. The cluster ONLY GROUNDS (originally) through the mounting screws.
Click to expand...
Will do. Grounding the switch makes the dashlights work. Turn signals are unrelated as far improper function. They act more like a goofed up turn signal cam. I'll have to look at the panel for a good grounding location
 
RedFish said:
OK "turn signal lights stay on" isn't clear. Which lights? anyway... when the turn indicators in the dash come on with the park lamps there is a loss of chassis ground at front park/turn fixtures. Park lamp current finds a ground through the turn circuit instead of through the bulbs base and fixture. Rear lamps can't back feed in this manner since the path is interrupted at turn signal switch for brake lamp operation.
So if the turn indicators in the dash are the issue, check ground wire connections at radiator support.
Click to expand...
Yes. The turn signal goes solid but doesn't blink and correct one lights up.
 
Ok Redfish. Here's what I have. I checked the ground at the radiator support. Terminals are corroded. Cleaned them with no change. They do come on, just no blink. Checked the bulb. Right bulb, not blown, changed anyway. It blinks! I don't think the bulb is bad I just disturbed the connection. I will be checking grounds and cleaning terminals. I'll get some dielectric grease and use it too. The car is clean and low mileage but never been restored. The wiring harness is in good shape but could use some tlc here and there. With all the help everyone has given, I think I'm on the right path.Thanks to everyone!
 
Update. Everything works. Headlight switch replaced with good ground. Dash lights work. Turn signals fixed. Turn signal flasher relay corrected the problem. No need to disturb the column
 
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