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A Harness Headache

Q. Are there any companies that sell replacement copper wire cable assemblies for the GM cars (79 Olds Cutlass Supreme & 82 Impala) to replace the aluminum wires that run from the fuse box under the dash to the tail light harness in the trunk? I have connection failures at each end where the connector pin is crimped onto the wire.


A. I am not aware of anyone who sells replacement wiring harnesses. I do know the aluminum wires have been a headache, especially for those who live in areas where salt is heavily in the air. These are areas like the northern states that use a lot of road salt and states bordering salt water bodies.

Aluminum wire is more prone to corrosion than copper wire, but neither one is impervious to the problem. I think the reason GM uses aluminum wire is because it's much cheaper than copper wire. If you live in an "salty" area, your best bet would be to solder the wire to the connecters rather than replace the wiring harness. If you're handy with a soldering iron or gun, it's not a difficult job at all.

What you will need for the job is a 40 watt soldering iron, some thin 60-40 solder, soldering flux and a harness connector tool. Do not use acid core solder. A harness connector tool has several types of pins to release the catches in the plastic connector housing to enable you to remove the connector itself. If you do not have any round connectors to deal with, you can make one out of a piece of coat hanger. Take a piece of hanger about 6 inches long and file one end flat about 3/4" long. You might want to make a couple of different sizes. I made several from old antenna masts. The top piece has the knob on the end and they are less likely to bend when you use it. If you have to deal with round connectors, go to a parts store and buy one, they are not expensive.

To release the latch in the harness end, unplug the connector and look in the housing where it plugs into the device. You will see a small latch, push the wire into the housing to relieve the pressure on the latch and slide the tool into the housing. When it is fully inserted it will open the latch and you can then pull the connector out of the housing. It takes a little practice to get the feel of it, but once you get the hang of it, it's easy. Do this one at a time so when you are done, you can replace it and not worry about crossing a wire. Note which way the connector is oriented in the housing so you can replace it in the same way. The depression on the connector must match the catch on the housing.

Okay, now you have the connector out. Plug in your soldering iron and let it heat up. I always use an iron and not a gun. The iron is easier to use, you don't have to wait for it to get hot between wires and because the wattage is lower, you won't melt too much insulation. The most important thing here is to clean the area where the wire is crimped. If it is not clean, the solder will not stick and you will get a bad joint. Use fine emery cloth or better yet, a "toothbrush." A small, fine wire brush you can get at an auto parts store made from brass or steel. Clean the area until it's nice and shiny.

This is the part where an extra set of hands will be handy. Apply a drop or two of flux to the joint. Now hold the wire/connector out straight and flat and touch the hot iron to the bottom of the joint and allow a four or five seconds to heat the joint. The flux will melt and sizzle and flow into the joint. Touch the solder to the top of the joint and it will melt and flow into the joint. If it doesn't, give it more time to heat up. Don't apply the solder to the tip of the iron, just to the top of the joint.

It doesn't take much solder to do the job, just enough to cover the wire and connector. You know you have a good solder joint when it appears even with no bumps or balls. When you're done, let it cool off and insert it fully back into the housing. Give it a little tug to make sure the catch has engaged the connector. If all is well, repeat the same procedure on each of the wire.

It can be a time consuming process, but once you get the hang of it, it goes fairly quickly. The time and effort you put into it now will pay off later in electrical problems you won't have. Good luck and let me know how you make out.

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Additional Information provided courtesy of AllDATA and Warranty Direct
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