Volvo Repair: flicker oil light, oil pressure guage, engine wiring harness

Question
Today i just did an oil change on my 87 Volvo 240 as i was coming home i noticed that my oil light went on.  very concern i pulled over and double checked if may i left something lose and i didn't everything was fine. well continuing  from my errands the light would flicker. what is wrong could it be a short or something easy to fix?

Answer
  Nick, First connect a mechanical oil pressure guage to the engine and be sure you have good pressure. Then check the engine wiring harness. Especially where it runs under the front of the motor. Common to deteriote there. Then check the wire that runs to the sender Itself. Often the insulation is rubbed off and the bare wire is touching the engine/frame.

Mark