Headlights and Fuse Panel Issues

Howdy all. I’m a little bit stumped on this. Working on my 70 Charger 500 that I recently bought non-running. Headlights work on high and low beam but seem kinda dim, swapped out the headlight switch and same problem. I checked the headlight relay and only have power to one terminal. Also the right most fuse holder, which is the dash light fuse, terminal gets really hot with the only headlights on. I can get the dash lights on by jumping from another fuse and wiggling the key up and down. I noticed that there wasn’t a body ground from the battery so I installed one. Can anyone point me in the right direction as to where to look next. The original harness hasn’t been hacked on by previous owners and seems intact. Thanks all

http://www.mymopar.com/downloads/1970/70ChargerA.JPG

http://www.mymopar.com/downloads/1970/70ChargerB.JPG

Here’s a couple schematics in case you don’t have.

I just got done with an entire rewire of 69 charger. Even though the harness looks intact, I would backtrack all the wires just to make sure. Old wiring! You never know. When I pulled all the wiring, some looked good but most didn’t. I’m a little curious why no negative wire on battery. May be as simple as it got old but with your fuse issues you’re talking about I bet it got pulled due to wiring issues so it wouldn’t catch fire! I would spend some time going over everything! One harness at a time!

1. headlights working, but dim --> That sure sounds like a bad ground or a half-dead battery.
2. headlight relay --> I don't know..maybe check wiring diagram?
3. hot fuse holder --> that's a short somewhere. With the battery disconnected, look at the back of the fuse holder....a lot of wires are bare & close together right behind that fuse holder...something crossed/touching? Also could be a short anywhere in that circuit.

I would start with measuring the voltage with a digital voltmeter. Measure battery voltage. Should be high 12's. Disconnect all of the headlight sockets, remove all the other light bulbs in the circut and measure the voltage. You should see only a small drop in voltage. If the voltage is good. The problem will be in a connection, switch, corroded ground connection. The problem sounds to me that the wiring circuit cannot handle the amp draw the headlights create....

Howdy and apologies for late response. Xp29h thanks for the wiring diagrams, they were a tremendous help. So this is what I found, 2 corroded/bad connections at the fuse box and loose ground at the steering column. Repaired those and so far so good with no hot fuse box. Also the previous owner cobbled together the alternator mounting, belt and bracket. I bought the correct setup from year one and the headlights stay bright. Thanks again y’all

Two things you might check...

1) Headlights ground. Follow the headlights harness, to the radiator support, where the wiring goes past the support. Should be a ground wire near it, ring terminal, that fastens to the radiator support itself. Check it for clean/tight contact.
If not...dim headlights.

2) Body/frame ground. Battery ground goes to the engine. Should be another ground, from near the rear of the engine, to the firewall...body/frame.