Parts needed: 2 old harnesses. One to rebuild, second for measurements. 4' 4 ga red power wire. 5' 4 ga brown or black ground wire. 20' 8 ga red power wire. 1 4 ga loop connector. 3 8 ga loop connectors. 1 8 ga spade connector. 1 2 ga loop connector. 2 nice battery terminal connectors. Aftermarket stereo connectors accept 4 ga wire with ease. Misc heat shrink tubing. 100 pack or so of 6" zip ties. New wire loom ( 1/2 in, 3/4 in, & 1 in)

Tools needed: Scissors. Wire cutters. Wire stripper. Small pocket knife. Wire crimpers. Tape measure. Lighter or heat gun. 10mm deep socket. 1/4 in drive ratchet. 3 in long 1/4 in drive extension.

The following takes about 5-6 hours to perform. This is not really a necessary upgrade, but nice to have and a good way to clean out the engine bay. For those who wish to run car stereos this is a must.

Procedure

1. Remove harness from car.
2. Remove all tape, wire loom, zip ties, and plastic mounts from the donor harness.
3. Lay out freshly stripped harness.
4. Find all wires you wish to upgrade. For example:
   • Main battery ground to chassis.
   • main transmission ground to chassis.
   • main battery power to starter.
   • power from fuse box to starter.
   • power from fuse box to alternator.
5. Measure out the wires stated in step 4.
   • All those that are 8ga make 4ga. This would include the two grounds and the power wire to the starter.
   • All those wires that are 10ga make 8ga. This would consist of the powers to the starter, alternator, and main from the battery to the fuse box.
6. One way to measure the wires is to run the new ones next to the old. This is easier due to the old wire not liking to lay straight from years of being loomed and the fact they are 20-30 strands of wire.
7. Take the two 4ga ground wires and stripped them back a bit. Then in whatever manner you choice twist together. This will be the end you put at the chassis ground. This is the end you need the 2ga loop connector.
8. Put all wire connectors on wire ends. Heat shrink any wires you may thing of feel need to be protected better.
9. Reconnect all wires where need be.
10. Now you will have a complete harness (again!). lay next to harness you didn’t cut up.
11. With the two harness’ laying next to each other starting at the fuse box. Measuring the stock harness begin making the correct wire branch offs.
12. You now have a complete harness less the loom. -
13. Get your new loom ready and layed out.
    • 1/2 in - 2 ft.
    • 3/4 in - 1 ft.
    • 1 in- 3 ft.
14. Zip tie newly loomed harness every 3 in or so. The 1 in loom will be a bit big for the harness towards the alternator side. You can roll it into itself like a funnel. Start at the alternator side and move towards the fuse box. This way you’re able to notch the loom where the harness branches out and pull it tight to the fuse box.
15. Make sure you loom the branches and smaller wires you want to first. This way you can use the bigger loom to hide any seems.
16. Reinstall the harness.

Throughout this guide you may also wish to remount the factory rubber mounts and plastic brackets, if desired.

Also see

• Ford Escort & ZX2 section for the entire index of all Ford Escort and ZX2 related articles.