Do you have the polarities right? The negative side is the shorter lead. To wire in parallel all negatives should be tied together and all positives should be tied together. Your 3V source has to be able to supply enough current to supply all the parallel circuits. If you wire in series by wiring each led's positive to the next ones negative which would be series you would need a 21 volt supply because you would drop 3V across each led. An led will not get brighter or darker with voltage changes. It will either turn on or off.
The interior is done. This was my first ever attempt at flocking. I used embossing powder. The entire gauge area of dash is a decal. I made dash panel cut from .010 styrene. to go over it and add some depth. I also made separate floor mats and door speakers. I need to find or make a radio decal for the dash.
I never depend on glue for chassis to body attachment. I have always found a mechanical solution that locks the body to chassis this takes care of any slight warpage and you do not have to mess with glue on a finished body.
I have the chassis done the engine is molded in but It looks pretty good painted. The exhaust system was two separate parts. I have the basic colrs painted on the interior. I am going to do carpet with embossing powder(1st try).
Can I ask what clear coat it was exactly? It looks like Glosscote the way it pulled up. Tamiya's clear(TS-13) and Testors wet look have better chemical adhesion. Glosscote just lays on top as a separate layer. I truly think Glosscote is a shellac not lacquer.