Check your wiring and a good ground is a must.
Did you get all the right sending units.
mech gauges and electric 2 completely diff things.
Adding auto meter to mine all electric except the boost gauge I had to change to all new sending units.
On mine the Phantom series the lights are a separate harness I made from the gauge electronics.
Im at a loss for you other than test them off a 12 volt source. Try Autometer tech from their site to see what they say.
Sounds like just not getting a good connection. Have any fuses in the mix?