Partial electrical out- Truck still runs/starts

[one_bad_rover]

Hey all.
So Im a bit stumped here and hoping someone might have insight on where to start.
1963 M35a2. Fire Truck Conversion. Has a remote 12v. system for lights and pumps.
The electrical keeps failing. And by failing I mean, I get in, turn the power on. Get the buzz. Truck starts up, no problem. But I have absolutely no lights anywhere else.
Batteries are new, everything appears to be grounded, but Im drawing a blank as to even where to start after checking all my grounds. Any suggestions, locations, etc... appreciated.
Thanks!

 

[dmetalmiki]

That is a beautiful looking truck.
However, If 'twas I, I would simply (Well not so simple actually) rewire to all 24 volt everything.(Especially if it is not a military conversion).
If like some Macks the electricals are running through inverters, then it can become a genuine nightmare.
A stock deuce harness would be a cure all if you are up for it.
My Diamond T was 24 12 6 volt!..Not any bloomin' more, It is ALL 12 Volt now.

 

[dmetalmiki]

I would like to see more pictures of all round that gorgeous truck. Please.

 

[one_bad_rover]

I would like to see more pictures of all round that gorgeous truck. Please.

Heres a load of pics from last week:
https://www.facebook.com/marketplace/item/697898200665219/

 

[dmetalmiki]

OK, Well actually as some of the kit in my M45-530c tfft has 12 volt units, I have fitted an inverter, Rather than taking power from the FIRST battery,
If you have problems with this circuit, Look for a "king sized cable" from the FIRST battery to power the auxillaries. Or seek out where the inverter is in the circuit (Of 24 Volts)..

 

[Sgt C]

Dont know if it's related but recently had a similar (not exactly the same) situation. After repainting I had headlights but no running lights, no turn signals, no dash or brake lights. The only thing disturbed during the process was I took off the turn signal lever from the steering column. Since I painted the column, I wondered if the turn signal body needed to be grounded. I took it off and noticed 4 small protrusions. I scraped the paint a bit and reinstalled the assembly. Everything worked after that. Haven't verified that the assembly actually grounds through the column on the schematics but it fixed my issue.

 

[SETOYOTA]

The turns signal does ground through the Column . Not much help on your truck with a home made harness.

 

[jerryb59]

I had trouble with no power on my 24 volt and 12 volt systems. I noticed that the light switch would trip every time i turned it on. It will reset after a few seconds. It turned out to be 2 wires going to the headlights that had rubbed together and shorted out.
The way i found it was by turning the light switch on several times and then i felt the wires until i found one that was warmer then the rest. then followed it to the short.
It took about a week of trouble shooting and scratching my head.
Hope this helps.