Grounding issue started with the horn.....

Update: Changed the headlight switch yesterday and got both a working dome light and dash lights. Looking into the solid state limiter from RTE (even if its not needed i hear it is good to upgrade it while the dash is out) to see if that cures the temp and fuel gauge issue along with the soldering that you have mentioned to sure up the connections to the circuit board. Still need to get the steering wheel pulled to trace the wire for the horns to find out why it will not ground when the ring is pressed. I'll change the gear selector light bulb when I am in there and I should have 90% of my lights working in the car now.