From previous response:
Chain 2 is accessed at connector block KT3 row. Double check row 'B' jumpers: 1-2, 3-4, 5-6, 7-8, 9-10, 11-12. Don't assume jumpers are good, pull each one and verify they were properly inserted and tightened on the wire and not the insulation. KT3 has deeper than normal wire pockets and it's easy to tighten on the insulation if you don't strip the wire back enough.
Reference the prints in the manual in the link in previous response, circuit diagram sheets 7 & 8.
I troubleshoot the 0V chain by putting the voltmeter (+) on the 24V [XT3-b15 or -B16] and use the (-) lead to follow the 0V thru the run-chain. If in manual mode, you must pull in the deadman to measure, I prefer Auto mode so I don't have to mess with deadman.
Start at XT3-B5 and if it is 0V, then keep going XT3-B6 up to -B12. You'll find the break in the chain somewhere.