Electrical problems

[windfisch]

Goodmorning question! I have a 87 freedom with a 89 cowling with headlight openings so I bought lites and wiring harness installed hooked up but lights won't work! I tested battries and found I have 6 volts on the two outside battries and only 12 volts on the two sets in the middle shouldn't they read 36 volts when I test them? The lites I bought are for a 12 vold system I've tried to use 2 battries one postive other negative but still no lites tested switch and only have 6 volts at switch,cart had tailights already installed but I'm not sure if I hooked everything up correctly they were working before I changed out to the new light switch! I also don't have the ignetion switch with light terninal on it. Could that be a problem? I have printed out a couple different wireing diagrams but not sure if its the right ones. This is a used cart I bought this summer and the previous owner screwed up wireing so cart wasn't running when I purchased it but somehow moving wireing around I got it to run with some sparking here and there,but I'm not sure if I have things correct. Can anyone out there give me some suggestions,besides buying a new cart? Thanks very much