[Cape Cod Bob]

I am planning the wiring for my sedan. I am using 1157 bulbs in the rear lights. They will be running thru a mid 70's GM steering column and a good brake light switch.
? Should I use relays to turn on the brake lights and keep the hi amps out of the steering column?
Also . should I also use relays to turn on the original headlights, 1930's new 12v lamps?
The fuse box I will be using was pirated from a towncar and has what aoppears to be a thermal interrupter. What was this protecting ? And can or should I put this to use?
Thanx for any ideas

[BlazinPlubes]

Goto Painless Performance, by the time you gather and buy all the parts and pieces and wire it all to gether (labor) you could have just got a ready made harness, universal that will work better and is designed to function correctly and has a warranty on top of that.

All great ideas, this isn't intended to tell you that it isn't going to work, its just easier.

[66GMC]

Each 1157 bulb draws 2.1 amps according to Sylvania so even four of them flashing at the same time hardly constitutes a "hi draw" or would even come close to the capacity of 16 guage wire.

Have a look at your fusebox.
I am betting that the signal flasher fuse is at least 15 amps.
I certainly cannot see any need for a relay.
-----------------------------------------
1930's 12-volt headlights? Are you sure?
I thought most automotive systems were only 6V until the mid-50's.
If they are 6V headlights and you run them on a 12V system, I would expect them to get quite bright for a very short time ... sort of like a flashbulb
----------------------------------------
Are there any ID #'s on this "thermal interruptor"?

Anything with a ford basic number of 14526 will be a circuit breaker, and the fusebox will likely be marked, no?

[Cape Cod Bob]

Thanx 66gmc for the reply. I appreciate the input.
So ,no need for relays makes the job easier.
The flashers have no amp ratings on them.
One is a wagner 323 ,3 lamp C90B-13350-A I assume is for turn sidnal.
The other flasher is a wagner 552, D2AB=13350 for hazard ?
The ckt. bkr.
is the # u posted.
The fuse box reference chart was missing and I could not find one in the boneyard to match. I will try again this sat.
As for the 1930's head lamps, they are 12v replacements for 6v cars upgrading to 12v.
I want to keep the old look and don't plan on night hiway drives
I just need some guidence as to what ckts. need what fuse to protect them
Thanx for any help.

[66GMC]

Yes, you are correct in your assumptions about those flashers. You could actually use two 552's in place of the 323 ... but not vice-versa, because of the maximum number of bulbs to flash.

As far as installing an appropriately-sized fuse goes, you should be able to determine the circuit load using a multi-meter, allowing just a bit extra than what the circuit draws.

Here is a chart that will tell you the maximum load that a wire of a specified guage can safely carry.

Let's say, for the sake of argument, that your headlights draw 40 amps. According to the chart, you will need a minimum of 10ga wire to carry that many amps.

While you're at the wreckers, check the glove box for the owner's manual ... as Ford usually included fuse location charts which described the circuit, fuse location, and the required fuse amperage.