1964 Ford Wiper Motor Wiring

Working on the Wipers in a 64 Ford

The 1964 Ford wiper motor is a simple but particular piece of hardware. It sits on the firewall on the passenger side, tucked behind the bulkhead. Getting the wiring right matters more than most people expect, because the switch does more work than you might think, and a bad connection will leave your wipers stranded mid-wipe or running nonstop at high speed. There are three wires coming out of the motor itself. Thick red from the battery through the fuse, black to ground, and a thinner wire that goes up to the wiper switch on the steering column. The switch then feeds power back down through a second thinner wire to select low or high speed. That is the basic layout. Everything else is detail work. The motor has two speed terminals inside. Low speed gets power through the switch on one contact, high speed on another. Park is handled by a cam on the motor output shaft that closes a pair of contacts when the wipers reach the parked position. If that cam is out of adjustment or the contacts are corroded, the wipers will stop wherever they want instead of parking reliably.

I stripped a ’64 Galaxie a few years back and the wiper switch had been bypassed entirely. Someone ran a permanent hot wire straight from the fuse block to the motor, hoping to skip the switch because it was faulty. The wipers ran full blast all the time and never parked. I had to trace the original harness first before trusting any replacement switch. The factory connector is a two-prong spade type that gets brittle after sixty years. Even if it looks fine, I replace it. The pins spread out and lose contact under vibration, which causes intermittent operation that makes no sense until you wiggle the connector while the wipers are running. Ground is another place where people go wrong. The motor case grounds through its mounting bolt to the firewall. That assumes the firewall paint is scraped clean and the bolt threads are tight. A lot of these cars have been repainted and nobody bothered to scrape the paint under the motor mount. The result is a slow, weak wiper that occasionally works harder if you smack the cowl panel. Sand the paint off the contact surface, use a star washer under the bolt, and retorque it. It should take about ten foot-pounds, no more. Over-tightening strips the sheet metal threads in the firewall and that is a real headache. The fuse for this circuit is usually in the fuse panel under the dash, numbered as slot four or five depending on whether the car has the extra circuits like turn signals or heater fan on the same block. Twenty amps is the correct rating. Anything higher and you risk melting the small-gauge wire that runs to the switch. That wire is typically around eighteen gauge and the insulation softens faster than you might think.

If you are doing a full harness repair, the factory color code for the power feed to the motor is red with a black stripe, the ground is black, and the two switch feed wires are both tan with black stripes but separate circuits inside the switch. Some later rewire kits get this wrong and use the same color for both speed feeds, which makes diagnosing a problem much harder. Pay attention to the wire gauge. The switch-to-motor wires carry more current at high speed than low speed, so do not substitute lighter gauge wire without understanding the amperage draw. The motor pulls roughly three amps on low and seven to eight on high. One thing that catches people out: the park circuit inside the motor is not independent of the speed selection. When you turn the switch off, the cam on the output shaft still has to make electrical contact to complete the park loop. If the wiper blades are frozen to the glass or the linkage is binding from corrosion, the park cam can jam and the motor will just keep trying to force it through. I had one where the lower bellcrank pivot was seized solid. The motor hummed loudly and the fuse blew on the next attempt. The fix was a penetrating oil soak overnight and then careful persuasion with a wrench, not brute force. Yanking the linkage free with the motor running is the fastest way to strip the gear teeth inside the reduction drive. For anyone replacing the motor itself, the new or rebuilt units vary in quality. Some come with the park cam pre-adjusted and some do not. Before bolting it in, bench-test it with a couple of jumper leads and a 12-volt source. Apply power to the main terminal and ground, then briefly touch the park terminal to see if the motor parks correctly when power is removed. If it does not park, the cam needs adjustment before installation. Trying to adjust it once it is mounted in the car is awkward at best and often impossible without removing the cowl trim and wiper arms.

The wiper relay, if your car has one, sits near the fuse panel. Not all 1964 models use a relay, but some do, especially if the car had the optional rear window wiper added later. A failing relay causes the wipers to cycle slowly or stop randomly. You can tap the relay housing gently with a screwdriver handle while the wipers are running. If they suddenly speed up or resume, the relay contacts are worn. Swapping in a known-good relay usually costs twenty dollars and saves an afternoon of diagnosis. If you need a wiring diagram, the Ford shop manual for 1964 covers this, and there are reproduction diagram sheets available from several aftermarket suppliers. The part number on the motor itself will tell you which variant you have, since Ford used slightly different housings between the Falcon, Fairlane, and Galaxie lines, even though the electrical connections are functionally identical. Check the tag on the motor before ordering anything. A mismatched replacement motor will bolt in fine but may not park correctly without modification.