Oil was changed in mother-in-law's car which is a 2000 Pontiac Grand Am 4 cylinder, 2.4 liter engine. Oil light keeps coming on and we've checked the filter and drain plug, not coming from there. We're now want to replace the oil pressure sending unit to try that. We have the part but she doesn't have a repair manual to go by and the library's non-fiction section is in storage and no store has a repair manual for us to buy for her. Can anyone help us with location of this part??? Thanks.