Seems like none of the universal headlight switches are actually universal. Just went through the experience myself, and if I had to do it again, I wouldn't. In fact, right after I got my new switch working a buddy at work told me he had five of the old ones from 1950s Ford trucks he had gutted. Oh well...
My adventure began with a broken old switch that was too far gone to repair, and I've repaired quite a few old switches. So I ordered something that looked darn close, and for only $15. It was very well made, at least as good as the original. Plus I really like how the circuit breaker mounts to it. Problem was the plastic bezel was metric, as was the (too-short) D-shaft. Plus the knob was tacky plastic junk, not that I planned to use it anyhow.
- "Universal" headlight switch - Guaranteed not to fit anything!
Unlike the original switch with a button release for the shaft, this one is permanently mounted. So, unless I could change it, it was worth nothing. Since I figured there was nothing to lose (except the parts inside) I opened it up by prying the tabs. A quick look inside and I realized I could make it work with parts from the original switch.
- Spilling its guts in the name of progress.
First, I had to snip off the indexing tab and tap the bracket to 7/16-20. This way I could mount it with the original bezel in any position necessary. A 7/16" outside tooth star washer on the back will keep it from spinning.
- Index tab removed. Tapped to 7/16-20 to use the old bezel. Didn't have to drill it at all, just went right over the old metric threads. Looks factory
Next, I cut the old shaft to length and slotted it to fit in the new switch. I did this on a mill at work, though you could just as well use a drill press or lathe. One catch here is that the white ceramic insulator for the dimmer rheostat was keyed for the metric rod. A Dremel tool with a cylindrical diamond grinder opened it up for the 3/16" D.
- The old shaft cut down and re-shaped to fit the new slider mechanism.
Lastly, I put it all back together (and forgot to take a picture). But here it is on the dash while I wire up the back side. Green painter's tape protects my rattle-can paint job from scratches.
- View from the front. The LIGHTS text is only upside down because I had the dimmer turned. It is in the PARK position here. When off it fits flush with the bezel.
- View from the rear. Wiring going in. I like the circuit breaker position. Very handy for accessory wires.
This project took me a year of thinking and not doing anything, and about an hour of actual work once I got going.