More issues with under dash harness, wires heating up...Fixed!

[Recovering Cuda]

Man, I'm here to tell you  that if things were to go smoothly for me I would not know how to react.  Listen to this.  Installed the new dash harness, took my time and hook everything up.  Had to figure out why two dash light weren't working and was able to fix that.  Prior to reassembling everything I tested all electrical components.  Now I've had a new light switch which I waited to install with this harness.  Anyway, plugged in the new switch and lit it up.  All lights worked, headlights, blinkers, sidelights, dash, console, glove box, ashtray.  I had also bought a new headlight dimmer switch.  Clicked it and the headlights went from low to high.  Great.  Then I put everything together, looks good.  Turned on the headlights and hit the dimmer switch.....headlights go off and both the headlight switch and dimmer switch heat up.  Hit it again and headlights come on and wiring cools.   This doesn't look that difficult.....what is the problem?......all advice, hints, suggestions welcome, except selling the car.....lol.  PS I know nothing about wiring and electrical circuits or how to use a volt meter, but my bother in law does.  hopefully someone and explain this to me in layman's terms.

[Recovering Cuda]

Something more I should add.  When the two dash lights that illuminate the left panel (over the head light switch and over the heater controls) would not work I found that they were tired in with the small light that illuminates the ignition switch.  These were not connected anywhere.  I found a loose connector that had two orange wires in it.  I made up a short piece of wire and ran the wire from this plug (plugged into the orange wire side because orange is for lighting under the dash) to the plug for the left panel lights....great they worked.  I don't recall checking the headlight switch after I made this jumper wire.   Could this be causing my problem with the headlight?   BTW....1973 cuda no a/c just plain.

[Bullitt-]

Are you using OE style headlamps or have you upgraded to halogens that draw more power?

[Super Blue 72]

Weird problem.  Anytime there is heat that usually equals excessive current draw as Bullitt sites an example of upgrading to higher amperage headlights. 

Another issue is a shorted circuit either the harness going to ground by cutting through the insulation or even of the dimmer switch is grounding out through the casing as it is metal or a short in the headlight switch but I doubt that.  Move the wiring around to see if the situation improves to see if may e something is touching metal.  Is the dimmer switch screwed to the floor pan?   If so try to lift it up so it isn't touching anything g metal to test if the casing is t grounding out to the floor pan.  Just a weird thought....

[Recovering Cuda]

Nope, no headlight upgrade.  The dimmer switch screws to the floor pan however, the dimmer switch plug has a plastic "foot" that the switch sits on when you plug it in.  I never thought of it before but maybe this "foot" is supposed to act like an insulator?  But if that was the case the screws pass through the dimmer switch and into the floor pan so it would still be grounded to the car.   I will pull it up later and see if when it's not screwed down I still have the problem.  I will also move the wires around.  This is a new harness so I can't see how it would have any abrasions that would expose wire...but any advice is welcome.

I'll let you know what happens.  Thanks

[Recovering Cuda]

Ok, I unbolted the headlight dimmer switch from the floorboard and laid it on the carpet.  Turned on the headlights and they come on, go to switch to high (or low) and they go off and immediately the plug to the dimmer switch and the plug to the light switch begin getting hot.  I also noticed that the ammeter gauge would be clicking and when I looked at that it was pegged to the left, discharge.  I moved the harness around as best as I could but this did not make a difference.  Could the dimmer switch be bad?  I'm thinking if the switch was bad it just would not work because this will cause a fire if left alone and surely this is not the problem.   I don't get it.  As I stated above, prior to putting everything back together the headlight dimmer switch was working.  After resembling everything I now have this issue.  Just for info purposes, there was no headlight upgrade, I have not touched anything under the hood.  All and any advice or suggestions are welcome.   Do I have to dismantle everything again and start over?  Like I mentioned above the only other thing I did was to kinda' jumper wired this plug to light up two dash lights that did not have power.  They are connected to the "orange" side of that plug which I believe is only for lighting-dash-console etc.  Other than that I didn't do anything else and everything else works.   

[Chryco Psycho]

Wires could be in the wrong positions in the plugs , sounds like you have a direct short to ground in the highbeam circuit

[Recovering Cuda]

Well, it worked before.  I will check the wiring on the new harness to the colors on the old harness and let you know.

[Recovering Cuda]

Well, checked all the plugs.  Everything is plugged in as is should be.  My brother in law was over and he has been analyzing the harness.  could be that the problem exists in the harness for the headlights under the hood. He found that it is going straight to ground he just doesn't know where yet.  He couldn't stay long and he is out deer hunting right now so maybe some time next week he will be back to do some further checks.  Just for grins I bought another dimmer switch.  Nada.....same issues.  I will let you know if this get resolved.

[Chryco Psycho]

it may just be routed the wrong way creating a high load not a short , it will heat up fast if it is a dead short .

[Super Blue 72]

Keep us updated!    Hope you figure it out! 

[Recovering Cuda]

Okay....up date.  Brother in law was over today to do more testing.  Basically everything was disconnected from the bulkhead connector in the engine compartment (headlight harness, wiper, engine harness)  even disconnected the rear harness for the tail lights behind the driver's side kick panel.  Also disconnected the heater fan plug behind the control panel.  He then jumpered those connectors for the headlights at the bulkhead and was using a volt meter.  It still goes to ground when you hit the dimmer switch.  He told me with nothing else plugged in the only location for the grounding would have to be in the new under dash harness. 

Chryco mentioned something routed the wrong way creating a high load and not a short.   Sorry, I'm ignorant....but what does that mean in layman's terms?  What do I look for?  Also, I will remove the instrument cluster and my bother in law wants to check a few more things with the cluster out.  Right now we think there may be a defect in the new harness.  After my bother in law checks it one more time and the problem remains I will have to deal with Year One.  Hopefully, I will be able to exchange it without problems. 

Anybody, feel free to pipe in.    Thanks

[Chryco Psycho]

If you have a wiring diagram trace the wires at the plugs , trace the wires from the headlight switch to the floor switch to the firewall , see if anything is pinched or in the wrong position in the connectors , possibly the high beam indicator in the dash is pinched or connected wrong

[Recovering Cuda]

Thanks, I believe my brother in law traced the wires, that is how he was able to test them.  Now we did find that the high beam indicator light is a single red wire which comes out of the harness behind the cluster with the other indicator lamps.  How much does this single indicator light play into my problem....if I can ask. 

I will remove the cluster today and see if there is anything obvious to the untrained eye.

[Recovering Cuda]

Okay,  I posted a message yesterday but for some reason it did not post.  Anyway, Cryco I think you have a point.   Yesterday I dropped the column and  pulled the cluster out.  I hooked everything back up (engine harness, head light harness, heater blower motor, rear tail light harness, connected head light dimmer switch etc)  With the cluster laying on the column I turned on the lights.   Guess what?  The headlights worked and go from dim to high....no heating of the switch wires at either the dimmer or light switch!  I knew I was not crazy because as I stated above I tested everything and everything worked.  The question is what is causing my issue?  I examined the wiring and I do not see anything obvious.  I did not see any pinching of any wires.    Any suggestions?