How do I hook into the harness for a two wire hook up for an aftermarket 28 ford brake light.

 

If it's like the old Model A tail lights (2 wires, one for run, one for brake, chassis ground so no wire), then it's pretty simple.

You will have to run a wire from the housing of the light itself back to ground on the bike.

I'll go take a photo or two of how I ran mine here in a little while and post 'em up.

NOW, if it's something else, I have no idea. Post a picture or a link to the light and that may help clear things up.

 

That is it. Model A with the glass stop lens. I would appreciate the pics

 

I would be questioning what voltage is it?? Back then they only had 6v now 12v you may need to convert.. and if you convert you may have different wiring set up 3 wire vs 2 just a thought

 

Sorry it took a while to get back - life sidelined me for a bit this afternoon, which, funny enough, was a wiring issue with the '40 Chevy.

Anyway, HD is right, if it's an original light or one made for a direct bolt-on for an unaltered restoration, cars that old ran a 6-volt system, and were chassis ground. I'm guessing that your aftermarket one is still set up as chassis ground, but IS 12 volt. Mine that I put on the Slim was exactly that, and it hooked up without any issue. Checking your paperwork that came with it, or checking with your source may help determine.

Here's the deal...



You can make out two holes in the back of the light, and two screws that hold the light to the bracket. There is a green wire coming out of the light housing on top, and a black one coming out of the light housing on the bottom. Those are your two "hot" wires for your STOP and your run lights. There is no neutral wire, since these cars ran the ground back through the metal car body. Since I didn't want to ground through my frame/bearings, I opted to go ahead and run a separate ground, which is the blue wire off to the left of the picture. I just put a ring terminal on a wire, and put a star washer between the ring and the screw that holds the light to the bracket, to make sure it made a circuit back to the housing of the light. SO... the wiring is as follows:

I'll use the colors that I have on my light. Yours may be different, but it should wire up the same way. Green wire is hot to the brake light. Black wire is hot to the running/license plate light. Blue wire is a common neutral wire for both lights. On the Slim, I just pulled off the old license plate bracket that came with the bike, which had wiring for a neutral and running light, but a blank for the brake light. Put those connections in to the new connector, and plugged it right in - piece of cake.

Running lights look like this:



And brake light looks like this:




Hopefully that helps!

 

If wiring diagrams are confusing, or if you already got the answer from my previous post, skip the rest of this one.

Here's a wiring diagram for a Model A.



The run/brake light is at the top left. You can see a green wire coming out for the brake light, and a black one coming out for a running light. You will also see a symbol for ground underneath the connections for both bulbs inside the housing of that light. THAT is your chassis ground. There is no wire going back to the other side of the battery - rather, the metal frame and body of the car acts as that wire. You don't want to do that to your frame, bearings, swingarm pivot, etc., so you will want to just add the wire to complete the circuit, as I explained in the previous post.

 

Perfect Ragnar, you hit it . Same setup. Thanks again

 

Got it hooked up, the first try would not work so I took you lead and made a ground the frame, now works perfect.

 

Glad you got it going. This "old school" stuff is cool, pretty simple, but man, can it be frustrating.

Post up some "after" pics, would you?