1974 Dodge Coronet with extra starter button

[72RoadrunnerGTX]

Thanks for that video!
Those Anderson Power Pole connectors look very good, that might be a good fix.
At my job (Caterpillar) we use Deutsch Connectors and I can get these very easily with the right pliers and everything. They're used everywhere and we have them with 8 pin connectors, but I have to check if they can handle the current for the starter switch.
I hope this will help get the lights and gauges working again.

I would caution that you only use the larger DTP Deutsch connectors (rated at 25amps) for the ignition switch wires, the more common DT & DTM Deutsch connectors can’t handle the normal ignition switch current loads. The Anderson PPs are rated at 45 amps.

 

[Maus]

I'll probably will use those Deutsch DTP connectors, my collegue will order them for me.
But what about these XT60 connectors? They can handle 60 amps.

 

[72RoadrunnerGTX]

I'll probably will use those Deutsch DTP connectors, my collegue will order them for me.
But what about these XT60 connectors? They can handle 60 amps.
View attachment 1822143

A bit overkill for that application IMHO

 

[RJRENTON]

A bit overkill for that application IMHO

Possibly the owner plans to do some MIG/TIG welding????
BOB RENTON

 

[Maus]

They're used in modelling a lot.
Like RC cars, boats, etc.

Anyway, I've ordered the (white) Anderson Powerplugs.
I'll keep this threat updated.

 

[Maus]

So I've replaced the burned Molex connector for Anderson PowerPlugs and although it looks nice, it didn't change anything.

So I started measuring from the battery, through the voltage regulator, through the bulkhead disconnect and through the fuse box.
12 Volts at the right hand side of the fuse, 0 volts at the left.....
Replaced the fuse and the oil and brake lights came alive!

Also, the pointer of the fuel gauge moves a little bit, but not enough, the fuel tank is full. I tried the trick with the battery cell, but that didn't work.
That tells me that the gauges aren't faulty, I just have to check a bit more. Starting at the sending unit and the multi connector at the back of the instrument panel.

Still, I'm happy with the progress I made so far.
Thanks for all the useful help guys!

And someone also messed up the seat belt interlock unit.

 

[Nacho-RT74]

If the gauges didn’t react to the battery cells, they are burnt

 

[Maus]

Well, not to be stubborn by any means, but I grounded the wires to the fuel and temperature sending units and the gauges came alive! I measured about 8 volts with a pulse at both wires. It came on every second.
But with the wires installed correctly at both units, the gauges went dead again.
So where to look next? I'm not an electrician, so I'm just trying to solve this.
Maybe both the temperature sender and fuel sending unit are fault? The fuel sending unit is new, the temperature not.
I can't start the car right now, so I put the temperature sender in a cup of boiling water, but nothing happened.

 

[Nacho-RT74]

Well… the problem are at senders then! Gauges are good.

My experience with repro fuel senders… sometimes the point misses contact with the coil track. Once I lost the reading, kicked out the gas tank and reading came back to live LOL.

The replacement gas senders are not known as a quality pieces, no matter the manufacturer. They are even linear reading and not logarithm reading like originals… soooo, the readings never will be accurate. BUT at least you will know when is full or empty.

I opened my replacement fuel sender and bent a bit the point arm to help on keep the reading allways on.

 

[Nacho-RT74]

About the seatbelt interlock unit… is not uncommon get it with rear cover lost. Plastic gets degradated and breaks easily at the touch. Now, who knows if was ever manipulated trying to get the interlock function bypassed

 

[Maus]

The fuel sending unit is almost impossible to reach with the fuel tank under the car, so that's going to be a challenge.
I could barely reach the connector. I know the previous owner installed a new fuel tank and a new sending unit, but he never tested it before installation.

I forgot to mention that the fuel sending unit wasn't grounded also. But I grounded it and nothing changed.

Isn't there a way to test the fuel sending unit while it's still mounted in the tank?
The temperature sensor is much easier though.
Oh well...it keeps me busy I guess.

 

[Nacho-RT74]

Officially you need to drop the tank to reach the fuel sender… although I have been able to get it removed with tank in place on my Charger. Tricky but doable if you know the shape of the unit and how to twist it while coming out.

Have you tried to kick the gas tank? LOL.

Test the fuel sender still in place? Well, checking ohms between body ground and sender stud.

Empty gets you around 72 OHMS
Full gets you around 10 OHMS
Half, gets you around 25 ohms.

But being linear, half tank could be anything