Deuce electrical system help needed

[crash69]

i have some electrical issues & i have looked at some of the service manuals
i am a service mechanic and i have yet to find a trouble tree or electrical
diagrams . any help in the right direction would be greatly appreciated.
by the way i am in the duece section but i have a 1969 m35a2.
fixed a problem with the alternator now have issue with turn signals & intermittent headlights.(already swapped the t/signal switch)
thanks.

 

[tiger422]

try light switch all lights run off it.

 

[crash69]

will do thanks

 

[Recovry4x4]

Wiring schematics can be found in one of the appendices in the back of TM 9-2320-361-20. The print manual has a nice pullout that is very easy to view. The PDF version can be printed in a large size at the local print shop and laminated for garage use. Stick it up to the truck with a magnet.

 

[Speddmon]

describe your troubles and we can help you out.

If you can decipher the schematics that Recovry4x4 pointed out you'll be doing good. There is also a great electrical troubleshooting section in TM 9-2320-361-24-1, starting with work package 11

 

[atankersdad]

I just had to address the electrical system on a deuce. I was getting over voltage.It was so bad that I blew out bvoth head lights and the oil sending unit. Pulled to alt and then started tracing wires. Had the alt bench tested and it was good. Found 2 things.The light switch was bad but the primary source was the existing Singars unit had a ground fault. It killed 4 batteries and caused 8 cuts to the rt hand getting the alt back in.

 

[crash69]

i was only getting 8 volts to the exciter circuit on the alternator i traced it back to a corroded wire coming through the firewall which led to the power flip switch.
the schematic is a little hard to read but it is a good start.
i also had high voltage when i first started the engine after the repair.
it calmed down i am sure it will be back. what is a singars unit & where is it?
fortunatly i have two trucks right now. so being able to swap parts is a plus.
i will try that light switch tomorrow,it seems a little soggy when you flip the headlights on.
oh yea i think this was a service truck (amber light on top, pullout table in the rear,
it also had what i call a portable aframe for overhead lifting)so there is no telling what got swapped out at times. as for my problem now the turn signal switch when turned left or right will light(on the switch) but not blink. no lights come on the t/signals themselves at all
with the switch activated. i have already tested the switch in another truck & its fine.
hoping the headlight switch is the culprit.
thanks again guys

 

[cranetruck]

Remember that all your ground returns to the batteries rely on the sheetmetal-to-sheetmetal bonds and ground straps, so check those first and reference your measurements to the NEG terminal of the (supposedly) grounded battery. Yes, it may mean one really long wire for your DVM or VOM.

 

[dittle]

Singars is a radio unit, does not come with every vehicle.

 

[GoHot229]

M35A2 schematic

 

[crash69]

alright changed out the headlight switch. headlights working normal no turn signal
no light with turn signal on.

 

[jblack6527]

alright changed out the headlight switch. headlights working normal no turn signal
no light with turn signal on.

interested in this, as this is where I am at with mine right now.

 

[poppop]

I can't provide much help just a comment. When I towed my Duece to the Ga Rally last year and hooked a wire to the trailer pulg so I would have brake lights and turn signals, The head lights on the Duece burned. I had to disconnect the turn signal switch to get the headlights off. Everything else worked fine when I unxcrewed the connection at the signal switch. There is a connection somewhere that ties them together. Problem is I don't know where. Electrical problems make my head hurt.

 

[derby]

What about the flasher unit on the driver side fire wall ?

 

[jblack6527]

..... Electrical problems make my head hurt.

Yours and mine both. I'm not sure if something happened to mine or not, but at first I wasn't getting any power from the turn signal switch to the flasher, changed the switch, and now I get power to the flasher, but none of the lights flash. I figure it is the flasher, but I want to make sure before I drop $50 on one.

 

[crash69]

i will swap it tomorrow i just had a similiar issue in my dump truck and it was the flasher

 

[crash69]

alright thanks derby for pointing out the obvious(i should have addressed that first)
the flasher unit (one on the firewall one on the inner fender)fixed the problem.
thanks everyone for all the input if nothing else i know where the wiring diagram is now