Typical Problems With Harnesses

A variety of trends are now apparent with refurbishment of dozens of harnesses. Some are due to previous owner's attempts for repairs and others are due to deterioration of the harnesses themselves.

• Broken and/or Exposed Wiring: Many wires are missing connectors, or have cut insulation exposing the copper stranded wires. Often times, we see splices into various wires to power various add-on items. Radio plugs are often missing.

• Burned Wiring: Some harnesses come in with various wires that have their insulation completely burned off due to a short in the system. Ammeter wires, neutral safety-switch wires, and courtesy wires seem to be typical of this problem. Some harnesses have experienced so much damage that they cannot be repaired in a cost-effective manner and thus become a source of connector parts.

• Molded Plugs: Surprisingly, many of the OEM molded plugs simply have too much resistance within the plug. 1967 and 1968 gauge feed plugs (i.e. oil, temperature, and coil lines) have a failure rate of up to 40%. When these plugs are encountered, they are replaced with OEM molded plugs that are good; if that is not available, commercial reproduction plugs are used. When these plugs are on the engine side of the firewall, we splice the wires on the passenger side of the firewall for higher reliability and to reduce the exposure of splices to the elements.

• Spade Pins: These are pins that make up headlight connectors, brake switch connectors, etc. About 25% of these connectors have high resistance, as the original crimps are no longer making sufficient contact with the stranded wiring. We re-crimp these connectors whenever they are found.

• Circular Pins: These are pins that make up the dash cluster connectors, ignition switch, door jambs, etc. These pins usually pass muster, although door jamb pins are a bit more problematic.

• Fuse Boxes: Pre-1967 fuse boxes were located where water can leak onto the fuse box, causing corrosion of the fuse clips. Post 1967 fuse boxes are prone to cracks and chips, but functionally, they are fine. We check all fuse clips for continuity and repair clips when required. Most clips can be removed and cleaned of corrosion. In rare cases, the entire fuse box is replaced.

• Wrapping Tape: The OEM used a non-adhesive tape, which worked well. Once it unravels, it can rarely be re-used. We use 3M 700 adhesive tape designed for electrical applications.

• Resistor Wires: Surprisingly, we have found very few resistor wire issues, with the exception of the braided sleeving. These wires have NiChrome cores, and cannot be soldered except with silver solder. However, they can be crimped without issue. We have procured both the coil (pink) resistance wire and the idiot lamp resistance wires for repairs.