James’ 1974 W200 build

I’m also having a power issue. I have a brand new AGM battery I bought today. I plug in all the wires from the bulkhead, all the little plugs from the front clip. I have power on the engine/ firewall side, but nothing in the cab side. No Headlights, interior, dash, cab, No key on power, absolutely nothing. I don’t know what the hell.
All I did was take the front clip off A couple Months ago and put it back on today