Chevrolet: 1977 Chevy P/U electrical trouble, high beams, electrical trouble

Question
Hi,
  I think I bought someone elses nightmare! A few months after I bought this monster,the tranny started slipping!Replaced that and it seems to be doing fine. Anyway Here is one of the many other small nightmares. When I turn on the headlights the dash lights do not light except for both turn singal indicators and guages freekout.
I did try different settings of the switches and this is what I got: Whith the dimmer switch set at lowest possition the guages are fine. When the high beams are on the temp guage shoots to hot  the gas guage drops to empty and turn indicators light up.Turn off the high beams and guages are normal again. Whith all lights turned off and either turn signal on or flashers flashing the temp guage will move and gas guage will slowly drop towards empty. Any Ideas?  whoever put the cd player in did not wire the memory sepperate from the power and wired the speakers wrong. The emergecy brake mount was missing a bolt. The emergency brake cable was routed so it would rubb againts the tranny mount man this poor truck...the previous owner's mechanic should be hung!LOL I think his mechanic was a monkey:)  

Answer
John ;
It sounds to me that someone screwed up the wires bad and also might have damaged the computer , I would try to look at all of the wires that were put in and than I would try to replace everything that was done to it, so remove the Cd and try to get all back to normal and wire the CD the right way. it might be a lot of bull work but it might be the only way to get it right.  ok
good luck !