Does one need to solder the wires into the spade connectors when wiring dynamo lights up? Or does crimping do the trick?
A good crimp with a proper tool is better than soldering as solder can make the wire brittle where solder wicks up the wire and cause it to break. If it's a dodgy crimp solder might help though.
Weeeeeell, actually, I do have some rather nice aerospace-spec crimping tools. But I did build the wiring harness for my race car, including a 12 channel datalogger, from scratch.
A good crimp with a proper tool is better than soldering as solder can make the wire brittle where solder wicks up the wire and cause it to break. If it's a dodgy crimp solder might help though.