If you are replacing a compressor or thinking about changing the compressor wiring harness, there are a few things that you should consider. There are some universal harnesses available, but they are often not a good choice if you are working with a particular brand of compressor, or a specific model. They may fit in the original location, but it is easier to get the correct length, or longer, if you use the universal harness. This is not always a bad thing though. You may need to be able to use an extension cord, or some other item, so knowing how far to extend it is important.
If you are replacing a compressor with a universal harness that does not fit the original harness, your best bet would be to use a shock mount style connector. This is what most people would call a universal harness. A shock mount connector connects the positive and negative terminals together, making it possible to use a cable with different terminations. The shock mount style connector will have different lengths available as well. Using a certain combination of cable lengths is necessary to be able to move the power around, without damaging the electrical wires. This helps make it easy to use new components without problems.
All of these different parts can be found on eBay. When purchasing a harness, it is best to go directly to the vendor or manufacturer for the type of harness that you want to replace. If you do not have a vendor or manufacturer, you can go online to the manufacturer and inquire about different types of compressor wiring harnesses that are available. There may be different styles available that can help you out. Most of the time you can find different options for both the internal wiring and the connectors as well.