1936 electrical problem

Henry Hopper

Henry Hopper

Senior Member
Last night I took delivery of my new car..a 1936 Cabriolet.It fired straight up and ran great, however the lights don't work,the brake lights don't work and the horns don't work.I downloaded the diagrams from Vanpelt and have spent the day trying to get things sorted.

First off I checked the " fuse" I say fuse but it is a little oblong box that is sealed, I searched online and it appears to be a circuit breaker from a 40 Ford( I think), anyhow I have continuity through it..next I removed the switch from the bottom of the column and checked it out..cleaned it( although to be honest, it was spotless)I checked to see that the main supply wire in was working, ..it was.I opened up a headlight and a tail light to see if the bulbs may have been blown by someone trying a 12 volt jumper maybe but they seem fine.The wiring seems to be in great condition and not the usual brittle mess usually found....

One thing I did find is that the wires that seemed to be attatched to the central plunger part of the switch, the brass bit with the spring on it, we're both broken off...at first I thought this was the issue but according to my reading of the diagram it appears they are the horn wires?

I've come in from the garage ,stumped....anyone care to suggest what the problem might be..TIA.
 

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First you may have to figure out how much of the wiring has been modified or change from the original. If it is just replacing the fuse with the CB, wouldn't consider that an issue. If you have power to the light control switch, then the issue must be in the switch itself. One interesting point is that the brake light circuit is on all the time regardless of the light switch position. So if there is no power to the brake light switch, then the power is not really getting into the switch.
 
Try jumpering the circuit breaker...sometimes the points in them get bad...still reads continuity but with enough resistance so it doesn´t work well.
Easy test to rule that part out.
Next on my list would be connectors if the lights just went out from car standing.
 
You could also get a long wire with alligator clips to feed power to the HL and rear side of stop light ,and buy pass circuit breaker ect make sure the HL switch is turning engaged in the spider Ted
 
Was the forked spider still attached to the horn rod when you took the light switch assembly off the bottom of the steering column? When you turn the light switch to the left or right do you hear or feel it click into place ( one click clockwise for running lights, one click CCW for low beam, two clicks CCW for High beam). The button missing on the bottom of the horn rod prevents your horns from working. If the obvious isn't it, then follow Joe's advice and start checking the circuits.
 
I've been using my multimeter and have 6 volts where the yellow wire feeds onto the Bakelite plate..according to the diagram this is the feed in.

The info about the forked spider concerns me a little....can you explain where it is located exactly.When I had the unit apart there was just the Bakelite plate and the brass disc in the housing on the column end......when I rotate the switch on the steering wheel there is no definitive click as such but it does seem to rotate the disc...as far as I can tell...I could do with getting a helper tomorrow to operate the stitch while I get underneath and check.

It's a head scratcher for sure.
 
The forked piece has 2 tabs that points towards to the light switch assy.It has a spring behind it and slips on the square end of the horn rod and held on by a small horseshoe clip.If that is all there the tabs on that piece engages the bakelite switch when the light switch housing is properly installed on the end of the column with the wire bale holding it on.The horn button disc at the steering wheel has 2 tabs and they should be vertical to be correct.If your wiring connections are to the proper terminals you should at least have power to the brake light switch.Just take a small wire and touch across the terminals and bypass the switch-the brake lights should work if your bulbs are good and you have a good ground.
 
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The photos are of a Model A light switch I believe, but they are all very similar. As you can see from the wiring diagrams, the brake light wire is connected directly to the power in wire. That would be the first thing to check, if there is not power to the brake switch then there is not power to the light switch.
 

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Right lads.....I'll get stuck into it again tomorrow..refreshed.

I must admit that positive earth confuses things...all my career in refrigeration I've done fault finding by tracing live feed through circuits.
 
JSeery said:
First you may have to figure out how much of the wiring has been modified or change from the original. If it is just replacing the fuse with the CB, wouldn't consider that an issue. If you have power to the light control switch, then the issue must be in the switch itself. One interesting point is that the brake light circuit is on all the time regardless of the light switch position. So if there is no power to the brake light switch, then the power is not really getting into the switch.
Click to expand...

Good point about the brake light switch....mmmmm
 
Henry Hopper said:
Right lads.....I'll get stuck into it again tomorrow..refreshed.

I must admit that positive earth confuses things...all my career in refrigeration I've done fault finding by tracing live feed through circuits.
Click to expand...

There is really no difference between + vs - earth (ground) as far as troubleshooting goes. The live is still the live, in this case the negative post on the battery. Not that it matters, but this is the direction the electrons flow, neg to pos, LOL. All you need to do is reverse the way you use the meter black is the power feed and red is the ground.
 
I got back at it this morning.....after a lot of cussing and fiddling I found the problems.

I was getting 6 volts at the switch plate but nothing out of any circuit....this was caused by a weak joint that was only a couple of strands, enough to give a reading but not enough to carry any load..I remade the joint and then got lights except one headlight..this was down to a bad earth and was soon sorted.

Next up was the brake lights...feed in but nothing out....found the switch was stuck with crud....took it off and cleaned it and lubed the plunger.....what a fiddle getting it back into position, but I got there in the end.The switch only seems to work after a lot of travel on the pedal....I will have to look into how to adjust it .

So, after several frustrating hours I now have lights and a thorough knowledge of the wiring system, it's definately a way to get to know your car.
 
Satisfying, to have a problem solved with assistance and always learning and gaining confidence in electrical or mechanical systems along the way.
There is a reason for everything, the tricky parts are: to find it and then to fix it.
But the feeling after the process is great in my opinion.
Phil NZ
 
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