Another Dash Lighting Puzzle

[smitty_040]

Yes, I know. Another dash lighting post.….

Trying to track down where things are going off the rails.

1. Continuity - I checked every orange wire from each end point connection and all show continuity back to fuse panel. Checked the brown wire from fuse panel to dimmer and it has continuity. Checked the black/yellow wire from dimmer switch to headlight switch and it has continuity. Checked black/white wire to black/yellow wire and it has continuity.

2. Jumper wires. Eliminating both switches I added jumper wires from the black/white wire to the black/yellow wire on the headlight socket. Then added a jumper wire from the black/yellow wire to the brown wire on the dimmer socket. I show 11.72 volts at every orange connection point.

3. Light bar. When I connect the light bar to the 3 way orange socket and ground the bar to the dash, the lights don’t work. I checked the voltage on the 3 connections on the orange socket and all show 11.72 volts. The remaining two still show 11.72 volts when the light bar is plugged in. Did that to see if the light bar was shorting the circuit.
I then unplugged the light bar and took gator clips from the light bar plug to the battery terminal on the fuse panel and using the same ground, the lights turn on.

I also took a gator clip from my aftermarket gauge pod light circuit to the orange socket and no lights. These also work when plugged into the battery terminal of the fuse panel and using the same ground in effort to eliminate the light bar variable.

I am stumped. No other lights are plugged into the orange wire circuit other than the light bar.

 

[Challenger RTA]

I think you are missing the point light bar works when grounded to dash.you more than likely don't have a ground.rusty rivets or socket.look for something simple.

 

[smitty_040]

I think you are missing the point light bar works when grounded to dash.you more than likely don't have a ground.rusty rivets or socket.look for something simple.

The grounding point I was using was a bolt through where the light bar attaches. I also ran a ground with a jumper cable straight from the battery to the light bar. No effect either way when plugged into the orange circuit that shows voltage. When I plug into the battery terminal on the fuse panel, all is well using both grounding attempts.

 

[Challenger RTA]

Try checking battery and chassis ground.When you using jumpers you not using the cars ground. It's hard to I'm not doing myself. It may be a erratic broken wire.Ground or power.Believe it or not check the fuses. Very rarely a fuse will partially blow.Will show power but under a greater load will not work.same for a bum wire. I would remove the bottom dash bolts on each side clean and reinstall.

 

[smitty_040]

Try checking battery and chassis ground.When you using jumpers you not using the cars ground. It's hard to I'm not doing myself. It may be a erratic broken wire.Ground or power.Believe it or not check the fuses. Very rarely a fuse will partially blow.Will show power but under a greater load will not work.same for a bum wire. I would remove the bottom dash bolts on each side clean and reinstall.

View attachment 98234

I have a new negative cable with ground to block and ground to core support. I’m not by the car now but I think there is ground from block to firewall. I’ll check tomorrow.

The odd part is it’s only not working when plugged into the orange circuit. When plugged directly to the red battery port on fuse block it works just fine.

 

[smitty_040]

I can also swap the 5amp fuse to see if that helps as well.

 

[Challenger RTA]

I would look at the fuse and block connection. unplug turn signal flasher to see if it's shorting the circuit.

 

[smitty_040]

I would look at the fuse and block connection. unplug turn signal flasher to see if it's shorting the circuit.

Good call. I know I have issues in the signal circuit. That’s a whole separate issue. Was working on the inside while I had the seats out. No blinkers but have hazards. The left signal is on all the time in the dash when headlights are on. I’ll try disconnecting that circuit too.

 

[smitty_040]

Another day in the saga.

I found that the brown wire from the dimmer to the fuse block was bad. Process of elimination. Put power to both sides of the fuse and lights worked. Then to the center brown terminal of the dimmer plug and nothing. Easy enough. Pull the fuse panel and splice in a new wire. That’s where all of the issues were found. Burnt wires everywhere.

One positive note. When I cut out the burnt section of the brown wire and temporarily connected, my dimmer works.

Now to play contortionist and fix every burnt wire.

 

[Challenger RTA]

Was it the brown wire that overheated crossed over the other damaged wires?

 

[smitty_040]

That will forever be a mystery…. Didn’t seem to be?

 

[Challenger RTA]

The red fuse-able link looks to be ok.That's a plus. A previous owner my have unknown done the damage with there rocket science idea. Good you found it before it became a disaster.

 

[hemi135]

I feel your pain, I'm having lots of the same issues with my wiring under the dash. 52 years of previous owners and absolute butchery under the dash. This is no easy feat as most don't fully understand the brains of the vehicle, me included but I do have some basic knowledge. I ordered a new M&H rally dash harness and I'm starting from scratch with new wiring when I down the vehicle for the season. Good Luck

 

[moparleo]

Smart move getting a new harness. Old harnesses, especially ones that have had issues are a common problem with older Mopars. Grounding is the most common problem. Cleaning all connections and using dielectric grease to seal connections is one of the first things that should be done .

 

[hemi135]

Smart move getting a new harness. Old harnesses, especially ones that have had issues are a common problem with older Mopars. Grounding is the most common problem. Cleaning all connections and using dielectric grease to seal connections is one of the first things that should be done .

Rodger that

 

[smitty_040]

All of the wiring has been repaired. The dash lighting issue ended up being a combination of burnt tan wire lead to the dimmer switch and a loose connection of the orange lighting wire where it was connected to the fuse clip.

 

[Challenger RTA]

Thanks for the follow up. That's what makes this all work. I'm sure other have seen this and it helps them.