Hi Guys:
I've got a '48 F-1 (NJ registered as a '49) The headlight switch went bad and would not turn the headlights off, everything but the headlights would go off. Before I could stop him, one of my students pulled all the wires off the h/l switch. Now I need to know they the go. The switch has 3 posts on 1 side marked p, b, & h, and 2 on the other side marked r, & b reading the letters right side up and from the rear of the switch towatds the **** end. I thought the p=parking lights, b=battery, and h= headlights, but it does not seem to work that way. The parking lights stay on with the h/l ,the rear taillights don't work, the parking lights stay on when the switch is turned off, HELP !
It seems that everything I've touched on this truck has turned to poop lately. I had the carb re-built because it was leaking from around the accelerator pump area, and then the fuel pump started to leak, now this h/l mess. I love old trucks, but sometimes......
Pete

 

Hi Pete,

If you will send me a Private message with your "real" e-mail address, I have a simplified diagram of the Switch Wiring. I can't down load and post it here because it's Power Point. I'll send it to you as an e-mail attachment.

But for now the three letters on the left (as you are looking down on the switch from the top)
are from firewall to seat: "P" "B" then "H" those hook up to Parking Lights in the front; Battery (hot power source; battery; hot bus; or Instrument panel circuit breaker); and Headlights (down to high beam switch then to the headlights) - respectively.

On the other (right) side the two posts are marked "R" and "B" from firewall toward the seat. They hook up Running lights (rear) and again a Battery (hot lead, et. al.) lead.

There should be a bridge running diagonally from the right center to the left front that connects to the left side of a circular rheostat on the front of the switch. The rheostate is made of porcelien. There is a 6th tab coming out of the rheostat on the right which is connected to the instrument lights.

Inside the switch is a slide with small **** that make contact to the rivets holding on the tabs. A lot of times these slides break or stop making contact. If you replace the switch (and it sounds like it's time) be sure to get one with the same wiring set up (original) or rewire in accordance with the new switch instructions. It sounds like you may have two wires touching (a short) in your light bundle. That old braded wire gets brittle and flaky after 67 years (Me too).

May I suggest a shunt type disconnect switch on the negative battery post to disconnect the battery quickly in cases like these. That will probably help you out a lot when you get to "Horns 101"

 

Hey Pete

Also, besides checking for shorts in the wiring. Make sure you have the power source wires in the right places especially checking that you don't have the leads on the right side switched (battery wire on the "R" post etc).

 

48-50 didn't have the dash light rheostat in the headlight switch, just had a little toggle switch under the headlight switch to turn off the dash lights. 51-52 light switches are the same but with the rheostat. Most all after market replacement switches will be the 51-52 type.

 

DMPTRKR is absolutely correct.

But a lot of folks had replaced the stock set up with the 51/51 type or aftermarket. I should have been more specific. I think if the inst. lights are still on the toggle, they shouldn't be an issue in this scenario because their circuit is disabled by the toggle as well. But if Pete ended up with 6 wires at his headlight switch, I wanted to let him know where the extra one "should" go.....Wonder how he's doing?

Nice sketch by the way

 

Just wanted to say THANKS ! Yiu guys have helped me out so much trying to get my F-1 drivable, I don't think I could have found a better sourse for info & help than here.
Thanks to all of you !
Pete
'48 F-1