Recommended splicing method - Solder (For 16 AWG and Smaller Diameter Wire Only)

Disconnect battery ground cable.
Strip wires to appropriate length.

Fig 1: Identifying Wires Stripping Dimensions
Courtesy of FORD MOTOR CO.
Install heat shrink tubing.
Twist wires together.
Solder wires together.
NOTE: Use rosin core mildly-activated (RMA) solder. Do not use acid core solder.

NOTE: Use heat shrinkable tubes marked with ES-1 (16-22 GA) or ES-2 (10-18 GA) to seal wire splice.

Fig 2: Identifying Wires Soldering Dimensions
Courtesy of FORD MOTOR CO.
Bend wire 1 back in a straight line.
NOTE: Wait for solder to cool before moving wires.

Fig 3: Identifying Wire Bending Position
Courtesy of FORD MOTOR CO.
Evenly position heat shrink tubing over wire repair.
NOTE: Overlap tubing on both wires.

Fig 4: Identifying Wire Position Heat Shrink Tubing Over Wire Repair
Courtesy of FORD MOTOR CO.
Use shielded heat gun to heat the repaired area until adhesive flows out of both ends of heat shrink tubing.
Reconnect battery ground cable.

Fig 5: Identifying Heat Shrink Tubing Installation Dimensions On Wire
Courtesy of FORD MOTOR CO.