there is no power in the main red wire on the back of the light switch. which causes the dome lights, main power for radio, door locks, trunk release, all dont work. but the acc. wire for the radio works so all the other ones must run from the same main power wire. when they do work i turn the dome light on every thing shuts down on that power line.

 

You might want to inspect Fuse Link 'B' and it's connections closely. That should be the one that feeds lamp power on an '85.

 

where is fuse link b located?

 

That would be Fusible Link "A" that supplies power to that red wire and not "B". Fusible link "A" is located down at the starter solenoid and is one of the two fusible links attached to the same terminal lug. You can test it by gently pulling on it, if it stretches then it is bad.