I wouldn't just go throwing parts at it in an attempt to fix it - you'll end up not fixing the problem, spending a lot of money and getting very frustrated.
Let's see if we can get to the root cause of the problem and then address what needs to be done. There are a few things that need to happen for the compressor to engage.
First, you'll need the engine to be running, so once you get that far, we can continue with how the A/C system works...
The HVAC unit on the dash tells the PCM that it wants air conditioning by sending 12v out through the green wire with a white stripe.
This 12v signal goes through the Low Side cycling switch on the accumulator to the PCM.
Once the PCM sees this signal it says "OK, I'll ground the relay to engage the compressor clutch"
The most likely scenario, since you mention that it hasn't worked in 10 years, is that it's low on refrigerant. If there's not enough pressure on the low side cycling switch to close it, the PCM never sees the signal, therefore never grounds the coil on the relay, therefore never powers the compressor clutch, therefore never engages the compressor, etc.
Easy way to test this is to pull the connector off the low side cycling switch and take a paper clip and short the two wires together. If the clutch engages, go find the leak, fix it, get the system recharged and you'll be good to go. Just do this as a troubleshooting step - don't leave the clutch engaged for more than a few seconds.
If the clutch does not engage (remember the engine will need to be running), then we can go through a few more troubleshooting steps.
- Is there 12v at the low side switch?
- Is the 10A Prifan fuse good in the under hood electrical center?
- Is there power to this fuse when the key is on?
- Is the A/C Clutch Relay functioning/clicking?
- Is there 12v at the A/C Clutch Connector?
- Is there ground at the A/C Clutch Connector?
If the compressor clutch won't engage, it's a very low chance that the compressor itself is bad.
Check it out, and if what I explained above is confusing, please say so and we'll help you through it, step by step.