Plug to Headlight switch

[Pawned]

I pulled the dash cluster this morning to check the PCB and get an idea why the guages do not work. In the picture you can see that the nuts that make the connection from the gauges to the PCB is missing. So I took it apart to check and clean everything.
I went to reinstall the dash cluster and plug the headlight switch back in...... Until I saw this plug that I pulled out of it 3 hours earlier. I have no idea how this could happen. Looks and feels more like acid than heat did this. but there is no evidence of that. It could be deterioration due to aging plastic/rubber. It is impossible to find this plug, so I will have to wire it by hand

 

[67Dart273]

I can't help you with the headlight connector, but since you have the cluster out, do a little more

Make sure the PC board connector pins are tight, or go ahead and solder 'em to the board anyhow.

Take a good luck under the instrument voltage limiter. On mine, the brass contacts which the limiter plugs into were not making reliable contact to the board. I soldered them to the board.

Seriously consider buying or building a solid state limiter

Use "real" nuts on the gauge studs, not those fake tinnerman nuts.

You can "jerry rig" power to the cluster to test the gauges. Go to Radio shack and get resistors, substitute the resistors for the senders and you can check the accuracy of both temp and fuel. Hook them up through the limiter just like they'd be powered in the car

"Full" is 10-13 ohms, "1/2" is 20-25 ohms, and "empty" (or cold) is 70-75 ohms

For example, you can buy a four pack of 100 ohm, 1/2 watt resistors from RadShack and wire all 4 in parallel. This gives you a 25 ohm resistor to check 1/2 full and middle of the temp scale

 

[Pawned]

Are you referring to soldering the gas and temp gauge lugs to the PCB. I have already put nuts and washers on them tight, but I can always remove the nuts and solder them, which is not a bad idea.
I took the PCB apart and cleaned it. I used a spinning wire brush on the voltage reg lugs and reinserted them. I used the spinning wire brush on the rotary plug studs and and took each wire out of the holder and cleaned them. Tarnex helps remove the tarnish from inside the wire plugs. Then rinsed them in water and then used compressed air to dry them.
I checked each light plug and had to replace one. After all that was when I discovered the melting plug when I went to reinstall it.
I also got out my test equipment and applied variable voltages to the gauges to verify that they worked

Oh I see what you mean, yes I will solder them tonite

 

[67Dart273]

Was referring to the pins of the round connector to the PC board. Those are originally riveted and have a history of working loose. Sound like you got 'er.

 

[wjajr]

Thatheadlight switch mess is a result of excessive heat from corrosion and or lose connection. Corrosion acts as a resistancein any circuit; resistance = heat. As forthat switch, it is in a spot that can get wet from leaking windshield or wiperbushing. Also while investigating forwater damage make sure fuse holder and fusses are corrosion free to eliminateany additional problems.



Headlight circuitis one of the high draw circuits in these old cars. In addition to under dash corrosion abatement,pull headlights, and make sure each ground at bucket, and three conductorconnector the attaches to head light is free of corrosion. The headlight ground needs a good clean connectionto front sheet metal.



The bestsolution to correct poor headlight performance is to install a relay system poweringthem directly from battery with #10 conductors, and triggered via headlightswitch circuit. This removes highcurrent draw through headlight switch, shortens current path and voltage drop tolamps resulting much improved performance, and cooler under dash components.



Moredetailed relay conversion instructions here:

http://danielsternlighting.com/tech/relays/relays.html



Disclaimer: I have made this conversion using Dan’sstuff. It improved my old lamp’s light outputby a third.

 

[krazykuda]

That plug melted because of too much heat. If anyone has taken the dash apart and not put that connector on completely, or one terminal "walks" when trying to install the connector, it will cause a poor connection and heat up. I've seen this on many A-bodies.

 

[Pawned]

I continued with cleaning up behind the cluster. What a mess. The fuse box is a disaster- Only one fuse was sized correctly, 4 of the 5 fuses that were suppose to be 20A fuses were actually 30 amp fuses. The other 20 amp fuses had a 3 amp fuse in it. The final fuse that was suppose to have a 3 amp fuse in it, actually had a 3 amp fuses in it. There were wires to the fuses that were cut an taped. I think there was a fuse or two jerry rigged into the back of the fuse box.
The corrosion is terrible, not sure if I should try and clean it.