Blowing fuses in my '33
 

Gents,
First off, I'm no electrical genius by any stretch, but I'm wondering what causes the 25 amp fuse to blow that cuts out my lights and radio in my '33?
Let me back up and first say that I am driving a 49K mile survivor. The wire looms are 86 years old yet I've not experienced this light problem ever over the 54 years I've owned the car.
Problem started last week after an evening drive as we stopped for ice cream at a stand. Fired her up to head home and no lights. No ashtray radio. Checked the fuse and it was blown. Good news. Replaced the fuse and all worked, but just for a while. Blew that fuse. Then it happened again.
Any reason why the circuit is overloading or does a short somewhere in the loom cause the blow? Like I said initially, I'm no genius when it comes to electrical problems. Any help out there?
Thanks

Re: Blowing fuses in my '33
 

Does a wiring diagram help you any? The wiring on a 33 is fairly simple, but I know that doesn't help much if your not familiar with automotive wiring. The only wire on the exit side of the fuse is the Yellow/Red which goes to the light control switch a the end of the steering column (down by the frame). In your case there appears to also be a second wire to the radio which is not shown on the diagram. The Yellow/Red wire connects to the three terminals labeled BAT in the diagram (this is inside of the switch and not something you can see).

If the fuse is OK with the light control switch in the off position then the wiring should be OK from the fuse block to the light control switch.

I would next attempt to determine which circuit is causing the issue. I would try each position on the light control switch and see if you can determine which one is blowing the fuse. Might start with the parking light position and if that is OK, then try the high beam position and then the low beam position. Leave it in each position to be sure it is working OK.

The brake lights are also connected to the light control and is hot is all the positions including the off position. So, with the light switch in the off position if you step on the brake and hold it for a while that will check the brake circuit.

After you determine which circuit is blowing the fuse we can work on where the problem is in that circuit.

Re: Blowing fuses in my '33
 

I've just done a bunch of replacing wires on my '35 Fordor. If you have original wires they are copper covered with fabric. New style replacement is copper, jacket, and fabric.

I've found many places where bullet connectors have exposed copper that can lead to exactly your situation. I also found places where the fabric was just gone for an inch or more at a time. (BTW, are you sure the 25 amp fuse is right, I use 20 in my 35 and 36?) I'd start by going over what wiring you can find under the hood, horns, headlights, dash connection. Could be almost anywhere.

Visit VanPeltSales.com for diagrams...
http://www.vanpeltsales.com/FH_web/F...1933-34car.jpg
http://www.vanpeltsales.com/FH_web/F...wiring1933.jpg


I got my wires from Third Gen Automotive, Michael Driskell, or 35fordtn here on the barn. They came with diagrams to lead me through installation. You can PM him from his user page: https://www.fordbarn.com/forum/member.php?u=7302

Re: Blowing fuses in my '33
 

A 20 amp fuse is correct for a '33. The radio should have a separate fuse.

Re: Blowing fuses in my '33
 

Just read the 3 responses to my query and I appreciate all your help. Thank you. Before I go and purchase a new harness ( which may be the smart thing to do after 86 years of usage) I will systematically start checking all visible and accessible wires and connections according to the diagram and your suggestions. The connection at the end of the steering column will certainly be the hardest to address. As far as the fuse goes.... wouldn't a 20 amp fuse blow more easily and more frequently at this point?

Re: Blowing fuses in my '33
 

More than likely, a 20 amp fuse would blow more frequently, or at least sooner than a 25 would under the same "problem" condition. The 25 amp fuse (vs. the 20 amp) is probably only "band-aiding" the anomaly situation when it does occur. It's quite possible that you have a bare, exposed piece of wire that is somehow rubbing on a grounded surface under the right conditions which, of course, blows the fuse. DD

Re: Blowing fuses in my '33
 

I was leaning on that idea. Over the course of time something got exposed and is tripping the fuse. Well, intense inspection is now the plan. Thank you!!!

Re: Blowing fuses in my '33
 

Robb....please don't gloss over what DavidG indicated above. The radio has a separate fuse. Be certain that your radio is "off." Better yet, disconnect it from that 20 amp circuit. Now you can begin your search. Good luck, Pat

Re: Blowing fuses in my '33
 

You would be futher along if you determine which circuit is causing the problem so you know which wiring to look out.

Re: Blowing fuses in my '33
 

Check the wires that are no longer protected by missing/dried out rubber grommets where they pass through the firewall and fenders or any metal hole....

Re: Blowing fuses in my '33
 

Good point! Will do! Thanks

Re: Blowing fuses in my '33
 

Had a problem like that on my 33, turned out the brake light switch was bad. Easy fix.

Re: Blowing fuses in my '33
 

That's why you need to trouble shoot the problem instead of just jumping around all over the place!

Re: Blowing fuses in my '33
 

Good plan! Thanks