Red is positive.
Blue is negative.
The caps common joint is ground (negative pin from the cap with the red lead on positive and positive pin from the cap with the blue lead).

Martin

Hi

Thank you for your reply. Yes the red positive was my understanding as well, why I found it odd it was connected to negative on the first cap. 

Just so I understand you correct. The caps are seriel connected, so the order would be this: 

Cap1: Red Wire -> Negative Pin, Black Wire -> Positive Pin

Cap2: Cap1 Positive Pin -> Negative Pin, Blue Wire -> Positive Pin

No.
It's a positive (red) and a negative (blue) supply with a common ground (black).

Cap 1 Positive terminal RED
Cap 1 Negative terminal BLACK and also connected to Cap 2 Positive terminal
Cap 2 Negative terminal BLUE

Look at the schematics!

Martin

Yes, I did and, that is why I wrote here, cause if you see on the pictures that is not how it's actually connected originally. Unless the caps are marked opposite of normal caps? Marking on positive instead of negative?

You can trust how they were mounted from factory.
If in doubt put a voltmeter on.

Martin

I will, and I'm pretty sure red is indeed positive. But I'm afraid I don't know of a way to measure polarity on a capacitor, so should I assume that the polarity is marked with positive on the original caps, unlike what you would normally expect of modern caps where negative is marked?