I need to replace the oil pump and the oil pressure switch on a '99 Sebring Convertable but I no longer have the owners manual. I'm looking to find out how to do it and if there's going to be any special tools I need. Thx.

The switch / sending unit should be on the side of the block.
While it is true the switch / sending unit can fail, you should also know the engine bearings and oil pump can wear down and cause a drop in oil pressure.

It could just be engine cover. My guess.

It may be the oil pump. If the gauge is going up when the rpms increase it's probably not the gauge or pressure switch. If the computer senses the oil pressure is low it will shut the vehicle off to try to save it's self from catastrophic failure. Also it may start cranking longer before starting. Thats it building oil pressure before the computer will let it start. Make sure oil is full, clean & thick.

Generally, the computer only runs the pump long enough to start the engine and build oil pressure. After that, the oil pressure switch keeps the pump on, most of the time by supplying a ground to the fuel pump relay. This is a built in safety thing, when the engine isn't running, the fuel pump shuts off. Most public libraries have Chilton's manuals, or you could pick up a Hayne's manual at a store like Autozone. These books can help you locate the relay and oil pressure switch, as well as provide wire colors for your specific vehicle.

almost every fuel pump is in the tank now

sounds like someone forgot to reconnect a power cable from the battery to the fuse block inside the car, you might check this out yourself

Could be a bad oil pressure switch, or a bad oil pump. Both will cause this issue. Hope it is the switch b/c the oil pump is a costly repair.

do you have the 2.5l engine ?this is a very common problem with them Oil pump you will start hearing the valves ticking on start up when the engine is cold
i you have the 2.7 l just kiss the engine good buy oil sludge is a problem with that Eng that's why thay do not have any resale value

The most common problem is a bad oil pressure switch on the 99-02 grand cherokee with the 4.7l v8. The part has failed on 90% of all 99-02 grand cherokees I have worked on. The housing is junk,but since it has lasted longer then 36,000 miles the factory would not issue a recall. The oil pressure switch can be purchased at any outlet. but have found the duralast was decent. that being said Go to autozone and get part # PS471 (oil pressure switch for 1999-2002 N code 4.7L V8.) chances are if you encounter the same problem after replacement you will need to drop the oil pan and un clog the oil sump.

To replace the switch, under the hood look for the power steering pump on the driver side of the vehicle, to the right and under the p/s pump is the oil pressure switch, If it is wet, its bad for sure, remember to disconnect the battery before service,as not to harm the gauges.

If you are talking about the change oil message on your cluster. You need to press step until oil change mileage appears on screen and then just press reset.

If you are inquiring about the oil pressure swith on the engine there is no reset procedure. If you just replaced the oil pressure switch and still have no oil pressure, you are going to have to use a manual oil pressure gauge to make sure that you have engine oil pressure. If you have oil pressure with the manual guage there is a problem with the wiring or engine computer.