I'm installing a dual-element sparto taillight on my ls650 and I was wondering how to connect the 2 wires from the lamp to the three on the harness? Do I need to ground the black wire to the frame, solder it to the bulb socket or something else?

andylaughs wrote on 12/31/69 at 16:00:10:


Your new lamp has two leads to the filaments with the return via chassis ground (the metal housing, bolts, side rails, bolts, fender, bolts, frame.)  A few connections that could become electrically open.  I'm sure you've see cars which have wonky turn signals/taillights where the light dims insteads of brightens.  Same chassis groiund design, with a faulty ground.

Our Thumper does not rely on chassis ground for electrical return; we have a ground wire.  You could ignore it, and run the risk of an open chassis ground and wonky light operation.  Or you could but a spade or ring terminal on the ground wire and slip it under the mounting bolt of the new lamp to asssure a solid ground.

It's hard to explain what to do with 3 wires, when you don't know what they do.  Got spare fuses?