Left lights work...why won't the right?

I got some garage time today and was happy about it, although I would prefer it wasn't 110 degrees in the garage.

I am working on the electrical system. I am adapting the wiring harness from the 1992 Suburban I pulled the engine out of. I think I figured out the taillight wiring except only the left side is working.

The truck suffered damage on the front right side and the bulbs and such are busted up. Would there be any connection with the right taillight?

I am also wiring up the front turn signals/running lights. they are aftermarket 12 volt units for a motorcycle or hot rod. I wired them in and they work either as turn signals or running lights but not both. If the headlights/parking lights are on it won't blink as a turn signal. If the lights are not on the turn signal works fine. Again, I haven't wired the front right side of the car yet. Would there be any connection?

The engine isn't running yet so all of my testing is done with a strong Optima battery and the key in the accessory position.

Thanks.

sounds like a bad ground

Both sides have to be wired for the system to be functional and the bulbs need to match.

Thanks guys.

That is actually a relief.

Can I wire in extra grounds simply by splicing a lead off the black/ground at any point?

Or...I have some places where I have deleted something from the system and have extra ground wires. Can I just put an end on these and ground them to the frame or bodywork?

Thanks again.

I might actually get back out to the garage this week. Can anyone answer this question?

"Can I wire in extra grounds simply by splicing a lead off the black/ground at any point?

Or...I have some places where I have deleted something from the system and have extra ground wires. Can I just put an end on these and ground them to the frame or bodywork?"

Thank you