How do I change oil pressure sending unit on a 2005 CHEVY MALIBU

(1) 2006 Chevy Malibu Oil Pump failure ,the connection to p0315 - YouTube

Here is a picture of the switch,
Oil Pressure Switch

Do you have a 3.8L..?

How To Replace an Oil Pressure Sending Unit On GM 3 8l V6

Hi Melba,here's a link showing where your oil pressure sensor is and how to replace. SAVE 20 GET BONUS 10 GIFT CARD ON ONLINE SHIP TO HOME ORDERS OF 100 OR MORE

The sensor is located behind the starter, next to the oil send switch, the starter must be removed..

Here is a video of the removal of the front seats of a Chevy Malibu that is in the same series as your 2005 (this video is applicable for 2004 - 2012 model Chevy Malibu)
https://www.youtube.com/watch?v=2l5xLKNRa2g

That could be from not having any oil pressure "oil pump failure, clogged filter, etc" or from a faulty oil pressure sending unit. More tests would need to be performed but is it really an oil pressure light or is it the change oil light. More info would be needed

You don't yourself. The lube change shop or garage can do this (requires special tools or removal of the pan). for a 2005 you're likely in need of a flush. some models can have a dipstick installed, but its not necessary. Unless you have a serious leak of fluid or shifting issues, it's rare to lose fluid. If you are having issues, then start with a flush and inspection BY A REPUTABLE GARAGE. do not use a dealer or transmission shop, they will always find ways to seprate you from your $$$

well there are a few. They all send info to computer and to the gauges.do you have a specific one in mind?

sounds like a bad sending unit. if the check engine light is on and you get a code of p0463 then you have a bad sending unit.

This is almost always the sending unit in the tank. Test that (not so easy to access it).