1938 Chevrolet Question

I have a 1938 Chevrolet pickup that I purchased in restored (frame off) condition. I replaced the brake pressure switch today, and now have another issue...

Now I seem to have dead electrics... the headlights, tail lights, horn do not work, nor am I able to start the truck (the starting issue could be unrelated).

Do these things have fuses? If so, where are they located? If not, do they have some kind of circuit breaker that I need to reset? If so, where is that located?

Thanks in advance for any help!

 

IS THIS A 6 VOLT SYSTEM OR A 12 VOLT CONVERSION? Knuck From Indiana.

 

MODELA30, it is the original 6 volt system...

 

Explain no start...does it crank or not? If it does not try to crank over, I would be looking at the battery terminals or at where it bolts to a solenoid. A 6v needs great connections, compared to 12v.

 

The light fuse was, if I remember right, on the headlight switch. These trucks also ran a bunch of stuff through the horn relay. Curcuits at the horn relay are not usually a problem unless some one has messed with it.

 

Do you have a FACTORY shop manual? If not try to get one. They are probably available in reprints.

 

F&J... the truck will crank (turn over) but not start. The headlights, taillights and horn are all dead.

 

Did everything work before you replaced the brake light switch?? Did you make any sparks when changing the switch??

 

Old Buzzard... everything did work fine prior to replacing the switch. Yes, I did accidently allow the two wires going to the brake pressure switch to touch and there was a brief spark.

Do the wires need to go back onto the brake pressure switch in a certain order (one terminal is longer than the other) or does this matter?

 

Probably doesn't matter. It should just connect power to the wire going to the lights.

I'm trying to remember the wiring but it was over 50 years ago.... If your spark was to ground you probably blew a fuse. Check the light switch for a fuse as mentioned. Depending who rebuilt the truck there may or may not be more fuses.

If the spark was just a small one between the two wires it was probably just lighting the brake lights.

Probably a corroded or loose connection somewhere.

 

It cranks over so the positive and ground cables are ok. The main feed wire goes from the battery cable terminal on the starter to one side of the amp gauge and from the other side heavy wires go to the light switch and voltage regulator. As stated, another constantly hot wire goes to the horn. Check both sides of the amp gauge with a test light or volt meter; if one side reads but not the other the gauge is bad and nothing works. If neither side shows a reading then the main wire to the starter terminal is bad. To start the engine simply run a jumper from the battery terminal on the starter to the + side of the coil, IF, the coil doesn't have the factory armoured cable and cap.

 

THOSE OLD TRUCKS IF I RECALL HAD RELAYS AND NO FUSES UNLESS THE PREVIOUS OWNER INSTALLED THEM. FOLLOW THE WIRES FROM THE BATTERY TO THE FIREWALL AND SEE IF THERE IS A BOX OF SOME SORT AND SEE IF IT HAS FUSES OR A RELAY IN THE BOX (TIN BOX IF I REMEMBER CORRECTLY) DISCONNECT THE BATTERY AND THE WIRES TO THE SWITCH CHARGE UP THE BATTERY. WHEN THE BATTERY IS CHARGED CHECK FOR POWER DOWN FROM THE BATTERY TO THE BOX TO SEE IF YOU HAVE A BURNED OUT FUSABLE LINK. YOU SHOULD HAVE POWER TO THE BOX IF YOU DO NOT THEN I WOULD ASSUME THAT SOMEONE INSTLLED A FUSABLE LINK IN THE WIRE AND IT IS BURNED UP POSSIBLY FROM GROUNDING THE POWER WIRE FROM THE SWITCH YOU CHANGED TO GROUND. Knuck From Indiana.

 

Discovered the problem... There is one 30A fuse behind the ammeter and it was blown.

Fuse replaced and lights, brake lights, horn all work and it starts great.

Thank you for all of the help!

 

was the fuse mounted to the back of the ammeter? or is it something someone added?

 

It is a more modern style (Bussman glass tube type) fuse and fuse holder, but according to the wiring diagram, there is only one fuse, located behind the ammeter...