What solder to use on basic automotive wiring?

I have the crimpers in post #2, for spade terminals (fork or ring), and for "butt crimps" if I were to use them (not). For the "56 terminals" in most Mopar connectors (new), I use smaller crimpers that fold the sides around in tight semi-circles like the factory did. I found those at Fry's Electronics for ~$18. I usually solder after crimping, since it makes me feel good, though many say you don't need to and/or shouldn't. To connect 2 bare wires, I use solder w/ heat shrink.

The solder should flow into the wire itself. Heat the wire and let the wire melt the solder and wick it in. Don't touch the iron to the solder and try to drip it onto the wire. Your iron tip should stay "tinned". Periodically wipe it on a wet sponge and re-coat w/ solder to give better heat transfer. You must have flux-core solder, or even better separate flux (rosin), and wait until the flux is bubbling. You can clean the flux w/ soap & water or citric cleaners.