Electrical Unit Set 56501

[Backlash]

The biggest concern that I would have with the bulbs, is them getting too hot and melting the plastic lights..

Big John,

If you don't know the voltage, and wanted to be safe when converting the Bulbs to LEDs, just use a resistor that will suit highest voltage found in the truck, which is probably the main batter, so approx. 8.4 Volts..

As for Latching the brake lights.. You could probably go lo-tech and do it with 2 small relays..