Electrical Issue....NEED HELP!!

[1carlover]

My 67 Coronet r/t with console still has no dash lights. I have gotten some good leads here on FBBO in trouble shooting the problem but after months of trying, I still haven't found the cause. I have no dash lights when the headlights are switched on. Has anyone in 66-67 b body had this problem and what did you find? I have seen posts for 68-69 cars with this problem but nothing for 67. Does anyone have a sketch or description for the wiring contacts for a 67 headlight switch? All other dash functions work as they should on my car as me and several others have checked for low voltage or short to ground issues but still no dash lights. The only parts that haven't been replaced are the neutral safety switch in the console and the console harness but no issues with that circuit. Any additional help would be much appreciated.

 

[super-bee_ski]

Well, shucks...that sucks
A complicated issue with many directions to "start troubleshooting"
Is power coming to the Switch?
Does switch have a potentiometer/rheostat? (AKA Dimmer)
If so is that dirty?
I'm not certain...
But is it a serial circuit? Can 1 bulb take out the rest?

 

[Mopars & Missiles]

I'm not certain...
But is it a serial circuit? Can 1 bulb take out the rest?

Are you saying he's got a "serial killer" in his car?

 

[Cheapsunglasses]

I agree with super-bee_ski. Dirty or bad dimmer switch, it’s a common thing with rheostats. Check for volts, and if you have volts rotate the dimmer dimmer switch, and see if it works

 

[1carlover]

Well, shucks...that sucks
A complicated issue with many directions to "start troubleshooting"
Is power coming to the Switch?
Does switch have a potentiometer/rheostat? (AKA Dimmer)
If so is that dirty?
I'm not certain...
But is it a serial circuit? Can 1 bulb take out the rest?

Yeah tell me about it. The headlight switch is new and is the one with a rheostat. The switch gets power and all lights, flasher and turn sigs work as they should.

 

[1carlover]

Well, shucks...that sucks
A complicated issue with many directions to "start troubleshooting"
Is power coming to the Switch?
Does switch have a potentiometer/rheostat? (AKA Dimmer)
If so is that dirty?
I'm not certain...
But is it a serial circuit? Can 1 bulb take out the rest?

Forgot to mention while dash was on the bench I replaced all bulbs and sockets and they all lit.

 

[1carlover]

My 67 Coronet r/t with console still has no dash lights. I have gotten some good leads here on FBBO in trouble shooting the problem but after months of trying, I still haven't found the cause. I have no dash lights when the headlights are switched on. Has anyone in 66-67 b body had this problem and what did you find? I have seen posts for 68-69 cars with this problem but nothing for 67. Does anyone have a sketch or description for the wiring contacts for a 67 headlight switch? All other dash functions work as they should as me and several others have checked for low voltage or short to ground issues but still no dash lights. The only parts that haven't been replaced are the neutral safety switch in the console and the console harness but no issues with that circuit. Any additional help would be much appreciated.

 

[1carlover]

I agree with super-bee_ski. Dirty or bad dimmer switch, it’s a common thing with rheostats. Check for volts, and if you have volts rotate the dimmer dimmer switch, and see if it works

I have 2 brand new switches and have tried both with same result when installed. I attached the dash circuit board to an old harness to test both the switches and the dimmer works the dash lights on the bench.

 

[RemCharger]

Did you check that power is going through the fuse. Sometimes sanding the fuse connections is necessary.

 

[1carlover]

Did you check that power is going through the fuse. Sometimes sanding the fuse connections is necessary.

Yes no fuse issues with new m&h harness and fuse block.

 

[gtx6970]

take a volt meter and ck voltage at circuit board.?

Take same meter and ck for ground on opposite side of lamp socket

 

[1carlover]

take a volt meter and ck voltage at circuit board.?

Take same meter and ck for ground on opposite side of lamp socket

I haven't been successful in figuring out why the rheostat no longer works the dash lights but I was successful today in bypassing that circuit altogether by connecting the constant 12v terminal on the headlight switch to the dash light circuit in the fuse block and my dash lights now work when the lights are turned on. Nice and bright with the leds installed.

 

[Big Bad Dad]

I once had a break in the printed circuit board on the back of the cluster in my old 69 Coronet. I fixed it by soldering a small jumper wire across the break. May not be your problem, but might be worth pulling the cluster to look at that circuit board. If I remember correctly, all of those twist out bulb sockets get their power from the board.

 

[mopar 3 B]

I haven't been successful in figuring out why the rheostat no longer works the dash lights but I was successful today in bypassing that circuit altogether by connecting the constant 12v terminal on the headlight switch to the dash light circuit in the fuse block and my dash lights now work when the lights are turned on. Nice and bright with the leds installed.

Were those plug and play leds?

 

[Coronet_Arch]

I had some loose connections on an M&H wiring harness. Check for loose wires at the connector to the headlight switch or the pins at the instrument cluster.

 

[lebshiff21]

I haven't been successful in figuring out why the rheostat no longer works the dash lights but I was successful today in bypassing that circuit altogether by connecting the constant 12v terminal on the headlight switch to the dash light circuit in the fuse block and my dash lights now work when the lights are turned on. Nice and bright with the leds installed.

What kind of LEDs? Some are very finicky about voltage variations and it's possible your rheostat doesn't provide exactly enough to fire them up?

 

[super-bee_ski]

Yeah
This stuff happens ALL the time
Everyone here has seen this stuff
Remember the old adage: "FM" means Fuc___ing magic?
1. we know you are NOT an idiot...
2. Grounding circuit is probably the cause
3. as lebshiff21 mentioned, LEDs are subject to finicky performance, especially Chineese made

I would do this for my first step:
1. Get to the dimmer switch, it has input lead and output lead
2. Take multimeter and "nick" input lead to dimmer switch...take DC voltage reading insuring "Input Voltage" is present
3. Then "nick" output" lead, verify output voltage

In electrical troubleshooting..there are simple methods developed to find the issue
This would essentially be a part of the "Half Split" method.
Divide circuit in half...check front portion and then check back portion

IF...if you have power coming into the dimmer switch...and no DC power coming out of dimmer switch...we can come to a conclusion.

Let us know

 

[super-bee_ski]

What kind of LEDs? Some are very finicky about voltage variations and it's possible your rheostat doesn't provide exactly enough to fire them up?

America is seeing a lot of failures from new LED systems coming in from China
Good point!

 

[mopar 3 B]

Who needs dash lights anyway?

 

[Cheapsunglasses]

If your dash lights don’t work, then when the officer comes to the window, you can say nope don’t know how fast I was going