Rewiring the Willys was needed since the original wiring had insulation that looked like it was about to come apart, and under the hood there were a lot of wire splices where the wiring harness had been adapted to a different engine. In my day job, I design industrial equipment, which includes a lot of electrical parts. At work, my equipment has to pass electrical safety tests and certifications. So when I looked into the original wiring, it is no surprise that I wanted to change a few things.
The original wiring had some issues:
Wiring Harness, Charging System & Starter
Getting a GM 12 volt alternator (12si with a 10si fan) that puts out 80 amps was a start. I was going to be adding a few electrical items; electric cooling fan, turn signals, a radio, electric wipers and maybe air conditioning. I decided on a wiring harness from Painless. I got a universal system intended for a truck that gives longer wiring to the rear lights. I put in battery cables and an alternator cable from Custom Battery Cables. I used a smaller group 35 Optima battery, since the full size one does not fit in the stock battery tray. The starter was from RobbMc Performance.
The vacuum-operated wipers apparently could be rebuilt to work, but electric wipers seemed like a better way to go. I could get intermittent and multi speed wipers, and maybe a washer spray in the process. So I got an electric wiper motor from New Port. New Port does not list this motor on their website anymore, so calling them may help. I also got a switch made by New Port to control the wipers - this is covered on the Dash page.
Eventually the turn signal lever would be integrated into a new Saginaw steering column. But until I replaced the steering, I got a turn signal lever assembly off of eBay that clamps to the steering column. This turn signal lever has a provision for emergency flashers and a switch for high beam headlights.
The outside lights were mostly OK. The headlights were fine, and the rear tail lights had running and brake lights. The brake lights would also work as turn signal lights once the turn signal switch was wired in. There were no backup lights in the rear turn signal units, but until I changed out the transmission there would be no way to make them work anyway. The front running lights had a single filament bulb, but the socket was set up for dual filament bulbs. So this wiring was connected to the turn signal switch and the bulbs were changed out with dual filament yellow bulbs to give front turn signal lights that kept the original clear glass lenses and the original look of the grille.