i just wired up my gauges but the lights are opposite when i turn the truck on the gauge lights are on and when i turn the truck lights on the gauge lights go off.

 

Seems to me when you wired the wires to the headlight switch, you wired it backwards. If there are more than two wires to the light switch, I would try different combinations until when you turn the lights on you get it right.

 

Use the #10 fuse in the cab for your power supply. That way your gauge lights will go on, off and dim like the rest of the dash lights.

 

X2 ^^^
What he said

 

Thats what I did ...