Wiring harness installation
Pro
Joined: Nov 2016
Posts: 729
Likes: 118
From: Kelowna British Columbia
Should be straight forward if reputable harness. I would take wiper motor off and bench test as per Willcox site. Remember the ground for heater motor and wiper motor are common to each other and because the black runs down near the starter a lot of people have put on starter positive. Do not make this mistake. It goes to engine ground.
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,065
Likes: 4,199
From: US-PNW
That looks like a Lectric Limited harness. I replaced both harnesses (headlight and firewall) a couple months ago in my '72. It's a straight forward job, especially using their diagram. Did you get that? If not, I can scan the one I have; it's for a 454 automatic but I'd think the main component connections are the same and only the couple of engine's and transmission's solenoids and sensors are different.
To connect to the fuse block, you'll need to remove the center screw holding both harnesses to the firewall. The two harnesses are joined with a sliding dovetail sort of arrangement, so you'll need to pull both fuse block connections off as one unit and then remove the firewall harness from the headlamp harness. Installation is the reverse. Leave the goop on the new harness and don't clean the old goop from the old one or the fuse block connectors. It's a dielectric grease to aid connectivity and keep corrosion to a minimum.
It's a satisfying job to do because all the wires and connectors FIT and aren't broken, spliced, brittle, or gone...
To connect to the fuse block, you'll need to remove the center screw holding both harnesses to the firewall. The two harnesses are joined with a sliding dovetail sort of arrangement, so you'll need to pull both fuse block connections off as one unit and then remove the firewall harness from the headlamp harness. Installation is the reverse. Leave the goop on the new harness and don't clean the old goop from the old one or the fuse block connectors. It's a dielectric grease to aid connectivity and keep corrosion to a minimum.
It's a satisfying job to do because all the wires and connectors FIT and aren't broken, spliced, brittle, or gone...
Burning Brakes
Joined: Jul 2018
Posts: 979
Likes: 258
From: Maryland
Did you need to do anything, or much, from under the the car, or could you access everything from above? I don't think I have their diagram unless it's in one of the boxes or folder with a lot of paperwork and receipts that I got from the previous owner. He is/was very thorough, so it might be in there and I just missed it. Thanks.
When you are done, do not immediately hook up the battery, make sure you test for shorts or grounds - I did this by putting an ohm meter across the battery cables (of course make sure they are disconnected from the battery) to ensure there were no shorts before I hooked it back up - better safe than sorry.
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,065
Likes: 4,199
From: US-PNW
Did you need to do anything, or much, from under the the car, or could you access everything from above? I don't think I have their diagram unless it's in one of the boxes or folder with a lot of paperwork and receipts that I got from the previous owner. He is/was very thorough, so it might be in there and I just missed it. Thanks.
Another tip is to take a minimum of 4 photos of the firewall - one under the driver fender showing the fuse block and routing, one from the driver fender to the center, center to passenger fender, and under the fender for the heater/blower - before you take the old wiring out. That way you have a reference in case you get confused on routing or components.
I'll take a photo of my diagram and attach it in a bit. The engine and trans are still out of my car, so I can easily take photos of the installed harness if you need something detailed.
Last edited by barkingrats; Aug 9, 2020 at 06:42 PM.
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