Dash Lights Troubleshooting

[72CustomCuda]

Hey guys

Trying to nail down a few electrical issues in my 72 Cuda...I've searched other topics but am not finding definitive answers.

First, a few things to consider:

1. Gauge cluster is out and off for rebuilding
2. Radio is not installed
3. Dimmer switch reads under 20ohms
4. Headlights work fine
5. Dome light works fine
6. Horn relay is on order-so horn and buzzer system are down
7. All bulbs are new in the dash light relay

Since I've had the car, the dash lights have never worked and indeed I did not even have the relay prior to getting a rallye dash light panel. 

Questions:

1. Will the dash lights even come on without the radio installed?  In another thread an individual said he got them to work by joining the radio harness wires together with a 10amp fuse...I tried the same thing but they didn't come on.
2. Will they come on without the gauge cluster installed and hooked up?
3. Which female wiring harness does the dash light relay plug into?  I assume the three holed orange wire, but most of the wiring diagrams I've seen (none specifically for the Barracuda) point to a yellow wire (which a single female'd yellow harness exists)...see picture.
4. What else can I try to troubleshoot?

Thanks for your help fellas.

[Jamiez]

What exactly are you calling the dash lights?  The light bar? Almost everything on these cars uses the body for the ground.  If you have the light bar out and are just running power to it, it won't work.  You have to run a ground wire from the light bar housing to the body (the dash frame normally does this).

[72CustomCuda]

The four light rallye dash lights housed in the rallye dash light bar...yes.

So the light bar needs to be grounded to the dash frame...makes sense.  Is this a separate wire or is the bar grounded when you screw it into the dash frame as a part of re-assembly?

[JayBee]

Is this a separate wire or is the bar grounded when you screw it into the dash frame as a part of re-assembly?

No separate wire. Yes, it's grounded when it's screwed to the dash frame.

[72CustomCuda]

Awesome...I'll try it later tonight.  So, given that the radio is out, they should still work when grounded or does the radio need to be installed?

[Jamiez]

The radio shouldn't need to be installed.  The power plug to the radio has 2 wires, but they both supply to the radio and don't go anywhere else.  One is the light, the other is to power the actual radio.  I guess it's possible that the wiring could run through the radio plug and transfer on to some other device...but that would still work unless the plug was cut off?

You can just run a wire from the dash frame to one of the screw points on the light bar and that will ground it.  Or you could just reattach it to test it.

[72CustomCuda]

Working!

For the record: the instrument panel lights do run through the radio and the radio circuit must be completed (inserting a 10amp fuse into the radio harness does this nicely) in order for the lights to work.

So the lights work great now.

Final question:  should the dimmer switch dim the light panel lights?  My intuition is no (the switch doesn't dim it now that it's working...) because there is no indication that the orange instrument panel lights route through the dimmer switch.  Which means the dimmer switch powers the lights that insert into the cluster (right?  Can't verify because the cluster is in Virgina being refurbished) and will be grounded when installed. 

Correct me where I'm wrong.

[Jamiez]

The dimmer controls the light bar and if rotated all the way to one direction the dome light.  Odds are your dimmer has corroded and no longer works.  This is pretty common.  Slotts is your man for a replacement.  He'll take your old one as a core and sell you a new one with stainless steel components that won't fail.  My own dimmer only worked through about half it's range, I purchased a rebuilt unit from Slotts and you can see the difference:

[72CustomCuda]

Slotts...how do I get ahold of him?

[72CustomCuda]

It says Slotts's private message inbox is full...is there another way of getting ahold of him?

[72CustomCuda]

One more question: one of the items the wiring diagram lists as plugging into the 3 pronged female connector is a heater light...(the third being the ash tray light).  I have no idea what the heater light is...can someone explain/point it out to me?

[JayBee]

It says Slotts's private message inbox is full...is there another way of getting ahold of him?

Here's an e-mail address for him and a bunch of pictures of his work.

http://www.cuda-challenger.com/cc/index.php?topic=64880.0

As for that "heater light", I believe it's referring to the bulb above the heater controls.

[Slotts]

Thank you Jamie and John! I appreciate the referral and support.   

Jamie that before and after picture is too much. That's the first time I saw that one. 

Hey John, I am looking for a stocking Canadian distributor. 

Slotts

[Jamiez]

NP Slotts   If you like the picture feel free to use it if you need to