For reliable electrical connections, I use these types of tools:
Wire Terminal Crimping Tools
www.pbase.com/mainecruising/wire_termination (The Good, Bad, & Ugly of Crimpers))
crimpsupply.com/
If you're doing splicing(joining wires together), try these, as they are moisure resistant:
Sherco Auto parts
NiAc ™ Heat Shrink Butt Connectors. The splices are first crimped, and then shrunk down.
Adhesive Lined—Moisture Proof Low Temp. Cross-Linked Ionic Polymer.
10 Pack 100 Pack 1000 Pack
HSNRBS 22-18 Gauge Red NiAc™ $3.50 $24.95 $174.95
HSNBBS 16-14 Gauge Blue NiAc™ $3.50 $24.95 $174.95
HSNYBS 12-10 Gauge Yellow NiAc™ $4.25 $ 39.95 $269.95
NiAc Assortment SBA-HSN
30 Red, 40 Blue, 30 Yellow
$29.95
Similar types can be found at most auto parts stores, made by 3M.
Wire Termination Insulation & Sizes
Terminal Insulation Color Wire Sizes
RED
22-18 gauge wire
BLUE
16-14 gauge wire
YELLOW
12-10 gauge wire
RED
8 Gauge