The oil pressure switch is not screwed into the sump where the oil collects, so you would be ok to not drain oil.
Well done to you being safe and cautious though.

Your car has a faulty wire from oil pressure switch to light , the insulation of the wire has worn through somewhere and the inner conductor is making contact with metal somewhere.

Good news is it's likely your car is fine to drive.
A sensible check if you can easily touch oil filter is run engine , no need to drive car, as it warms up does the oil filter get warm? If it does that means oil is flowing through it. Do not burn yourself.

Worth saying again , well done to you
And
Your car is fine to drive after doing the does oil filter warm up check.

jackwhoo said:

Good news is it's likely your car is fine to drive.
A sensible check if you can easily touch oil filter is run engine , no need to drive car, as it warms up does the oil filter get warm? If it does that means oil is flowing through it. Do not burn yourself.

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Thank you! Yes, the filter gets warm when the engine run. Maybe I should try following the wiring. Its just a bit difficult as it is packed away in the engine. Lately I've heard a rattling sound behind the dash, could it be that the loose wiring was located in there? And thank you for helping me out, I truly appreciate it!

Yes follow the wire back from the pressure switch till you find the problem.
Reconnect the switch anyway.
The wire has a short to ground somewhere it could be anywhere be start at one end and take your time.

jackwhoo said:

Yes follow the wire back from the pressure switch till you find the problem.
Reconnect the switch anyway.
The wire has a short to ground somewhere it could be anywhere be start at one end and take your time.

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I'll do that next week I think. Right now I am preparing to defend my master thesis next week, so knowing that the car is probably fine to drive takes off a big load from my shoulders! So again, thank you

Very pleased to help.
Wishing you best of luck for your master thesis.
Jack

Simple check here, do you have access to a manual oil pressure gauge? If so connect it up and see what pressure you have, Sounds like a wiring /sender unit fault.