What Engine do you have..if its the 104 you must remove the lower oil pan to access the oil level sensor..It is secured to the crankshaft main cap with two bolts then the wire goes through the engine block at the PASS side.The Connector is secured with a slide clip that must be removed to push the wire through the block.You Will Need a NEW lower oil pan gasket and a can of brake clean ..Do NOT over tighten the lower oil pan bolts!
Takes about 30min to do...