Lost lights and horn 1930 cf

[Mars]

I suddenly lost my horn and lights. Starts and runs fine, gauges work. Fuse looks fine. Must be something at column base. Why out of the blue?

[keiser31]

Possibly have grease from the steering box seeping into the light CLUM switch at the base of the steering column. Has the steering box been restored?

Edited June 17, 2018 by keiser31 (see edit history)

[hchris]

Yep, Clum switch at the base of the steering column is where I would start, all of the wiring for horn and lights comes through there

[Mars]

Fixed it, it was the fuse I guess, changed it and bingo! Thanks 

[ckowner]

If you lost the horn and the lights, the problem would not be in the clum switch. The horn wire and the power for the lights are joined on terminal #1 of the clum switch. That is where you check for power. From #1 terminal the horn wire goes to the horn and then to the horn button through the steering tube. when the horn button is pushed the circuit is completed to ground. It is interesting that the wiring schematic in the 1930 DeSoto handbook appears to be incorrect since the tail light always has power from terminal 1 and the parking lights work through the clum switch on terminal 3 which is next to terminal 1. Order looking down the steering column  from  right to left. 1-3-2-4-6-5. I also don't quite understand the thinking between the high and low beam in the head lights. My 1930 DeSoto CK had a foot button installed when I got it in 1971. The wiring diagram on the clum switch shows the selection between filament high or low. The Mazda lamps which I have have 2 similar filaments, so I wired the car with the floor button and the clum switch to activate 1 or 2 filaments simultaneously. We also fabricated a mirror image of the tail light bracket to allow for dual brake lights and signal lights also using the single filament parking lights on the fenders. Some fancy 6 volt relay work!

All the best

Rick VanOene

1930 CK6 coupe owner

[ckowner]

The reason your fuse probably blew is because the fuse holder is held  by a rivet to the back of the ammeter. the connection here is very poor and heats up. I bypassed mine with a modern fuse holder. Nothing worse than a fire because of electrical failure. everything in the car on 1-30A fuse with a lot of #18 AWG wire (small braid)

[Spinneyhill]

As @ckowner says... we have all done it, just replaced the fuse and thought "fixed it!" when we we have done nothing of the sort. Find out what shorted to cause an over-current to burn the fuse. It sounds like you may have been given the solution already.