Instrument cluster goes out

New here but have read alot of the forum. Here is my situation. I am about to trade a 93 STS for a 91 TC. The caddy is smashed up and he wants it for the motor and trans. The TC's inst. cluster goes out when you turn the head lights on. The oil pressure light comes on when you turn a corner. Any thoughts on these items? The TC was used for his son's school as a project car and there was a lot of work done to it like heads, suspension, and various other things.

The cluster dims when the headlights go on and can be dimmeed further by rotating the switch. Could be a bad switch or ypu may get lucky and turn the knob and have an easy fix. Hope so. As far as the oil light I would need to know right or left turn? (giggling) no idea on that one. Good luck

Have you checked the oil level?