Is there an easy way to rewire my car?

November 1, 2012 | By Richard Prince

Question:

What is the easiest way, step-by-step, to rewire a 1957 Chevy, when I already have the wiring harness? Also, is there an easy way to install a signal light harness in a 1967 Camaro?

Answer:

I’m not sure if you’re asking me how to install the wire harness you have, or how to rewire the car using the old harness as a guide.

If you’re not going to install the old harness you have, the easiest way to rewire a 1957 Chevy is with a new OEM type reproduction wiring harness, which is readily available from almost every business that sells restoration parts for Chevrolets of the era.

If you want to rewire the car by, in effect, making a new harness yourself using the old harness as a guide there really is no easy way to do this.

Lay the old harness out on a large work surface and take off most of the wrapping material that covers the wires. Then go one at a time and cut new lengths of wire to match each of the old wires. The new wire should be the same type (which for automotive applications normally means stranded copper), gauge, number of strands, color and length as the old wire. You may be able to reuse some of the old connectors but some will have to be replaced. It may be difficult to obtain exact reproductions of some of the harness connectors but this won’t matter if exact appearance isn’t important to you.

As far as installing the signal light harness in your 1967 Camaro, I assume you mean the harness that extends from the signal switch assembly in the steering column to the main under dash harness, and there is really only one way to install a new one.

You need to remove the steering wheel and horn button components to get down to the cancelling cam/switch assembly. Remove the screw holding the turn signal lever and set the lever aside, then remove the screws that retain the switch assembly. The wires are soldered directly to the switch contacts on an OEM switch assembly so you can’t easily disconnect these. At the other end of the harness the nine wires each insert into a curved plastic housing.

The connector crimped onto the end of each of the wires has a little tab that locks it into the plastic housing. To remove each wire from the housing insert a tiny flat screwdriver into the plastic housing to press this tab down while simultaneously pulling gently on the wire. The new switch and harness assembly normally has a new connector and you’ll need to remove this the same way in order to get the new wires down the channel where they should run in the steering column.

Use masking tape or some other method to denote which color wire goes in which position in the connector.

There’s a trick that makes it easier to get the new wires into position. Cut the old wires off at the switch assembly and tape them together. After removing the plastic connector housing from the new wire

harness tape the new wires to the old ones at the top of the column. Simultaneously pull the old harness from the bottom of the column and feed the new harness into the top of the column. Once the new harness comes out the bottom of the column remove the tape holding them to the old wires. Reinstall the new wires into the connector and plug this into the under dash harness.

My problem is that within three to five minutes of first

starting the vehicle and while still in “open loop,” the idle air control (IAC) motor completely opens, causing the engine to go into an extreme “vacuum leak” type of behavior.