Hooking up battery to newly rewired car

Sorry I am late to this party HERE IS HOW you do this---to prevent some mistake from smoking something important

FIRST do NOT just hook a multimeter in current (amps) up because if you have a "heavy" short it can damage some meters. Better meters, generally, Fluke, have fuse protection but those fuses are EXPENSIVE, approaching 10 bucks last I checked.

So, HOW? Easy, really

You want a big wattage 12V lamp. If possible, you want "a selection." Easy / cheap way is to use an old tail/ stop lamp socket, with an 1157 bulb. This bulb of course has two different wattage filaments. Best thing, you can wire this "tool" several ways for different jobs

For highest wattage, twist both socket wire leads together and use the shell for the other connection.

Connect either the shell or the wire leads, does not matter, to a known good ground point on the car. Connect the other terminal to your battery NEG post. This will create a series test lamp that NO MATTER HOW LARGE the short is, it will only cause the lamp to light

If the light does not light, or only lights dimly, you can assume that you at least do not have a heavy short

If it glows some, you can assume there is a load turned on in the car, such as the dome, tail, etc.

AT THIS POINT, if the lamp is less than "full brilliance" you can assume that it is safe to hook your 10A multimeter and determine how large the draw is.

Alternatively you can connect a SMALLER test lamp to "judge" the draw. Try your small 12V probe lamp. If that is "full bright" go back to your tail/ stop tool. Try using the shell, and the tail wire. This is a small wattage bulb and if it glows dim, you can have a smaller draw, like maybe the dome lalmp, etc.