The pictures above are a small section of bad harness that we took out of a 1984 244. The cardboard box holds the bulk of the old harness.

The main engine wiring harness is a bundle of individually insulated copper wires that connects various sensors, electronic engine control components, warning lights, and electrical actuators. Over time, and with exposure to heat, the insulation on the individual wires becomes brittle and begins to crack and flake off, exposing the bare copper wire. These bare wires are then prone to short out against each other or the body of the car.

Shorted uninsulated wiring can manifest in many ways depending upon which wires are shorted and where.

Some or all of the following symptoms are what our customers have reported to us over the years:

• Warning lights that won’t come on or won’t turn off
• Starter motor won’t turn on, or worse! won’t shut off
• Engine stalls
• Engine cranks over but won’t start
• Various other poor running engine problems

Inspection is simple, and at Popular Mechanix we take particular care to inspect the main under hood engine wiring harness any time the hood is open. We always recommend the wiring harness be replaced as soon as the earliest signs of deterioration are visible. Once the wiring harness begins to deteriorate it is only a matter of time before the car will fail to operate properly. If left unrepaired, more expensive repairs may become necessary.