Shane is right. Even if the Start Capacitor isn't the current problem, it soon will be and installing a new one may extend the life of the compressor. I always keep a spare in our trailer. I've changed a number of these at campgrounds for others, over the years. I could only do it because I always keep one on hand. When I get home, I order another one immediately.
BTW....... because this capacitor works on AC (alternating current), it doesn't matter which wire (from the capacitor) goes onto which connector that you remove from the old terminals. There is no positive and negative wire.
https://www.amazon.com/AMI-PARTS-Cap...s%2C181&sr=8-8