General Electrical Troubleshooting
Fuse boxes-there are three different types. The early models up to and including, the 67.5 model has a FOUR PLACE fuse box on the drivers side fender well tucked in by the clutch master. This one is no longer available(NLA) last time I tried to order one. If it is bad you will have to buy used or be creative. The '68 has a SIX PLACE fuse holder in the glove box. The '69 - '70 have a EIGHT PLACE fuse holder also in the glove box.
Poor grounds can kick your butt while trouble shooting. Roadsters have two main ground straps along with numerous other smaller grounds. The two main grounding straps are located as follows: One on the battery side of the motor and one ground strap from the starter to the frame. It is not uncommon to discover this one missing. If you see smoke coming from your throttle cable or choke cables-look for a loose or poor ground.
Brake lights not working? If they do not work at all try unplugging the wires from the brake pedal switch and connecting them together, bypassing the switch. If lights come on the switch is the culprit. These switches have been known to stay on sometimes draining your battery. Switch for the early cars pre 67.5 is located in the engine bay on the firewall and is connected through a junction block in the brake lines. Later cars 67.5 and above had the switch mounted on the brake pedal
For the lights that don't work on either side, unplug the plastic connectors in the trunk, (about 4 inches from the bulb assembly) and clean the contacts really well. Now might be a good time to use some die-electric grease on the connections too. Just a little dab will do ya!
If both your fuel gauge and temp gauge are not working or moving very slowly, the voltage regulator may be suspect. This small unit is bolted under the dash, just above the steering column. Make sure the connections are clean before replacing the unit.