Just for shits and giggles take a 12 volt battery and power the solenoid coil with it. See if it turns the engine over better.
I need some help please I just ran new oem harness with 7 wire turn signal in my 49 chevy and flashers and turn signals I got nothing ao I clean ground and buckets and everything I could then all of a sudden they were working again then nothing so I tinkered a bit then boom started working again then nothing and nothing since I've been messing with it for a week everyday for a few hours and I can't seem to get them to work I got my kit from y n z yesterday's
I would also suggest that you take all those little plastic collars off the various connectors on the wires and solder them. Better yet remove those connectors completely, slip some heat shrink tubing over the wires, solder new terminals onto wires, and then slide the tubing over the connectors and shrink. I would do this after yougetthestarting issue solved and a few each weekend. Those Crimson connectors are not the best. I know because I have used them and then replaced them.