Mark Houlahan
Brand Manager, Mustang Monthly
January 19, 2014

If there’s one constant, it is change. While some change may not be for the better or may be out of our control, modern technology certainly helps change the way we enjoy our vintage Mustangs. It wasn’t that long ago that to enjoy something as simple as power windows in your Mustang meant fabricating your own mounts and using salvage yard motors and switches to make everything work. Today, you can simply bolt-in a ready-made conversion with compact motors and electronics that require no cutting to your door shell and give you the modern convenience you use every day in your other vehicles. Now you can do the same with another such modern convenience—intermittent wiper speeds.

The vintage Mustang’s wiper system is sorely lacking an intermittent speed function. For those who drive their vintage Mustangs on a regular basis and who realize their cars will not melt when hit with rain drops (we salute you!), having the added benefit of an intermittent speed function for those light rains that just don’t quite require low-speed operation is essential to driving safety. Constantly turning the wipers off and on manually during driving in light rain takes your eyes and concentration off of the road. While intermittent wiper upgrades have been craftily created with later-model Ford switch gear for other year Mustangs, the ’67-’68 Mustang’s wiper switch design in the face of the gauge cluster makes it all but impossible to mount something in the stock location—until now.

Enter Muscle Car Switch to the Mustang aftermarket. Muscle Car Switch engineers have taken their passion for vintage cars and their expertise in electronic circuit design to create their first direct bolt-in intermittent wiper switch. Thankfully, they chose the ’67-’68 Mustang as one of their first projects.

The Muscle Car Switch intermittent wiper switch features five intermittent speeds and retains traditional low- and high-speed wiper functions while maintaining the stock footprint of the OE switch. Except for a minor difference in the switch’s control lever, you’d never know that the Mustang is fitted with a Muscle Car Switch and now has intermittent wiper speeds!

Even better, with Muscle Car Switch’s optional automatic headlight controller, you can ensure your headlights come on when using your wipers (state law for many) while still maintaining full manual control of your headlights, including high-beam activation from the floor dimmer. The wiring involved is mostly “plug and play” with a couple of basic wire connections and the mounting of the relays. We felt the two products make the perfect pair for driver Mustangs and decided to add them to our friend’s ’68 Mustang hardtop.

1 It’s best to remove the wiper switch control knob while the gauge cluster is still secured to the dash. An Allen wrench is all you need to loosen the set screw found on the bottom of the knob.
2 All of the gauge cluster attaching hardware is exposed and easily accessed except for the one rear-mounted retaining nut at the far right side of the gauge cluster. This is best accessed by removing the four Phillips head screws that retain the radio bezel and then reach up behind the dash to remove the nut.
3 The remaining Phillips head fasteners can now be removed. You’ll find three across the top of the gauge cluster, one under each large gauge, and two retaining the heater controls at the top (there’s no need to completely remove the controls). On ’67 Mustangs, there is one additional Phillips head screw above the heater controls.
4 Pull the gauge cluster forward enough to access the wiper switch connector and the switch’s two mounting screws. Disconnecting the speedometer cable from the back of the gauge cluster might aid in providing more room to work. Disconnect the wiper switch wiring by simply pulling the connector towards the front of the car.
5 Next, remove the two mounting screws (without losing them in the cluster or deep within the dash), then slide the wiper switch away from the gauge cluster to free it from its mounting.
6 The new Muscle Car Switch wiper switch, PNFM6768WI, differs in looks from the OE switch only in the control lever and it’s very slight. We’d surmise if you really wanted to reinstall the “wiper” knob you could file down the tip of the lever to accept the knob.
7 The rear of the switch features the same terminal locations and plug outline as the factory switch to allow the wiring to plug directly into the switch with zero modifications.
8 On the side of the switch, you’ll find this single wire terminal opening for the Muscle Car Switch optional headlight activation relay kit, PN M678HCIO. We decided to add the optional headlight activation relay kit, which turns the headlights on anytime the wipers are activated.
9 The Muscle Car Switch wiper switch is designed to bolt right into your stock gauge cluster. However, our ’68 Mustang had been upgraded with Classic Instruments’ gauge kit for ’67-’68 Mustangs. This required us to open the switch hole a little for clearance and drill two new retaining screw holes, as can be seen here. This is not required with stock gauge clusters.
10 The wiper switch control lever also required a very slight contour bend due to our Classic Instruments cluster because the large gauge body bumps the switch higher on the backboard.
11 The headlight activation relay kit is shown here. The system comes pre-wired and is a direct plug-in to the factory headlight wiring in the front of the car. The only additional connections required are the aforementioned signal wire from the wiper switch and a hot-at-all-times connection to the battery or starter solenoid.
12 The relay kit installation begins with the signal wire from the wiper switch being connected to the side of the switch. This wire will then be routed behind the dash and eventually through the firewall.
13 The wiper switch wiring connector can now be seated into the new Muscle Car Switch and the dash reassembled. We tucked the gauge cluster into place, but left the screws out for now in case we needed to do any troubleshooting.
14 The headlight activation relay’s trigger wire is passed through the firewall (we used an existing harness opening, but if you must drill a pass-through hole, be sure to utilize a grommet) and is routed to the left front inner fender area. The Mustang’s windshield washer bottle is removed here for working room and better photos.
15 The two relays need to be located close enough to the headlight wiring where it passes through the core support. Ensure the relay’s wiring ends will reach the headlight feed connection before drilling two mounting holes and securing the relay bases to the inner fender.