Mustang Gauge Feed Wiring Harness (1967-1968) Installation Instructions

Tools Required:
  • Small Adjustable Crescent Wrench
  • Tool to Remove Valve Cover Fasteners
Install Difficulty:
  • Easy
  • Easy Project
1. To start the installation of your new Mustang Mr. Mustang 14289 67SBW/OT-E Firewall to Engine Gauge Feed Wiring Harness, you have to remove the old one from your Mustang. In my case, the existing engine feed harness in my 1967 coupe was a disaster. The previous owners had hacked it up and spliced in new wires, and it now looked like a rat’s nest, so it was a challenge to remove. Typically, you should only have to unplug it and pull it out.
Mustang Firewall to Engine Gauge Feed Wiring Harness Install Image
2. Fortunately, the new Mr. Mustang harness is a simple, fast install and looks very nice and clean. Make sure the negative terminal of your battery is disconnected. Connect the three-prong connector (right side in photo) at the firewall. This is located next to the four-prong neutral safety switch connector (shown on left in photo).
Mustang Firewall to Engine Gauge Feed Wiring Harness Install Image
3. Run the new Mustang gauge feed wiring along the top of the intake manifold, just next to the valve cover on the driver’s side. From the factory, this harness was secured in place by three clips, connected at the front, center, and rear of the valve cover by the valve cover fasteners.
Mustang Firewall to Engine Gauge Feed Wiring Harness Install Image
4. Connect the red wire with the white stripe to the water temperature sending unit, which is on top of the Mustang intake manifold on the driver’s side. This connection just presses on to the stud on the sender.
Mustang Firewall to Engine Gauge Feed Wiring Harness Install Image
5. Connect the wire with the ‘shoe lace’ protector to the positive side of the Mustang ignition coil. Like the water temperature sending unit, this fitting just presses on to the positive coil stud as well.
Mustang Firewall to Engine Gauge Feed Wiring Harness Install Image
6. Finally, connect the white wire with red stripe to the oil pressure sending unit, found on the driver’s side of the block next to the oil filter. This connector will have a female spade bit. The oil pressure sending unit is likely to just have a stud. You can cut the connector off the wire and crimp on a ring connector and tighten down on the oil pressure sending unit with the correct sized nut, or for a cleaner install, use a spade adapter that threads onto the oil pressure sending unit stud for this purpose, as has been done here. The female spade connector can then simply slide onto the male spade connection on the oil pressure sending unit. After that connection, your install of the Mustang Mr. Mustang Firewall to Engine Gauge Feed Wiring Harness is now complete.
Mustang Firewall to Engine Gauge Feed Wiring Harness Install Image