New dash cluster lights won't light up.

Hey guys, so I've been restoring my late
uncles old 1982 K5 Chevrolet blazer. I
put all new fuses in the fuse box and the
lights all worked so I chechked the
gauge cluster and only one bulb was
working. I ordered some blue led bulbs
and replaced them all and when I turned
the key only 3 or 4 bulbs lit up. I cant find
any plugs I forgot to connect but there's
a place that looks like a three prong
connector would connect to. Also there's
3 of the copper connectors missing in
the plus I had connected but it seems to
me like if that was the problem all of the
bulbs wouldn't light up instead on just
some of them. Thanks in advance for
any help guys!