Does anyone know what to do before connecting to battery for a new top of dash clock? Thanks

I would highly suggest putting an in-line fuse on the hot wire to protect it. Those clocks are so hard to find and expensive to repair. Someone suggested this to me when I was putting mine in. I used a 1/2 amp fuse and it works great.

IThose clocks are so hard to find

I am surprised that no one has stepped up with a repro... Repro clocks and tachs for everything else...