Chrysler Repair: 2001 300M 3.5L oil light stays on while driving, low oil pressure, pressure gauge

Question
3.5L 88,000 well maintained miles - oil light is coming on after car is warmed
up - while driving - not just at idle.  Oil is not low, and has been changed
since this started occurring.  Could it be the sending unit, and if so, where is
it located?  

Answer
Hi Scott,
It could be the pressure sensing switch. It is located on the lower left side of the engine next to the oil filter. The switch has an electrical connector and it is associated with an accessory oil cooler and so there is a fitting for that.
You will want to lift the car on the left side and be prepared to catch oil that will leak out when you remove the sensor. Hold on to that oil cooler fitting when you unscrew the pressure switch so that it isn't moved/damaged. Remove the switch. Use thread sealing compound on the threads of the replacement switch when you intall it and again hold the fitting for the cooler.
The pressure light should not come on unless the pressure drops below 4 psi. You could put a pressure gauge on the fitting socket to actually measure the oil pressure or simply replace the sensor and see if that resolves the warning light problem.
I would get this resolved immediately, because if the issue is a true low oil pressure situation you risk damage to many parts of the engine.

Roland