Back-Up Lights Stay On / Dash Lights Out - Help?

[C30_Dually]

I just replace the light switch and plug on my '81 C30 (I kept popping fuses while trailering my race car, so I put a larger fuse in and ended up cooking the wire, plug, and light switch - word to the wise!!)

Head lights, running lights, and brake lights all work fine again, BUT, the back-up lights stay on all the time, and the Speedo and fuel guage lights don't work.

Did I blow those dash bulbs?
Did I rewire the running lights wrong? I replaced one wire at a time on the plug to make sure that I got them in the correct holes.

Any ideas out there?

Thanks in advance.

Dave A.
'81 C30 Dually