I have a 71 GMC K2500 with Factory Air. I finally got it back from my paint and body guy. I bought a new heater control unit from LMC, to include all new cables. During the reassembly process, I’m having a hard time remembering the cable routing on which cable went where. I’ve looked and looked online trying to find a routing diagram and I’ve come up empty handed. So I was wondering if you guys had an idea how to help me. This also leads me to my next thought, I’ve debated on upgrading to a vintage A/C system which from what I see and understand a much simpler system. Is it worth the cost? Or should I just use my 40+ year old equipment?