i have all the ground wires on all the spots im suppose to, but if i turn on the high beams while the car is on the tach will stop working the temp gauge goes right to H, and the blinker signals light up on the cluster. as soon as i turn high beams off everything goes back to normal. any ideas what it is going on?

 

Check the grounds where they go into the cluster istelf, I've seen them broken off at the back before.

 

i replaced all the grounds with new thicker grounds and made sure they were connected on the cluster. the battery cables are tight also.....would it have to do with the wiring for the high beams since it only does it when you turn the high beams on?

 

I would try checking the bulbs in the gauge cluster. I know if you blow a brake light, it could short the bulb filement out on the tail lights causing your dash and tail lights to come on so maybe something like that might be happening with your dash lights.