No oil pressure but no SES light

[im1choto]

I have a 2005 Suburban, that had the oil changed by the STEALERSHIP in mid December. Got it back and was reading high on the oil pressure level. Then with in a week the level went back down to normal. Stayed there for about 2 weeks then all of a sudden dropped to a level at the gauge of zero and below. We changed out the oil pressure switch/sensor and figured this would solve the problem. At the same time we changed the oil and the filter and everything smelled burnt! The oil had only been in the car for about a month and probably 1500 miles. I bought an oil pressure test kit and cant get it to fit. Just want to make sure we are trying to install it in the correct location, please let me know where it needs to go. Also, I have not had any check engine or SES lights illuminate. I am at wits end, can someone please help me?

PS the car only has about 65,000 miles on it. I wonder if it could be the oil pump causing these problems?? Please any help is appreciated.

 

[im1choto]

OK....connected the oil pressure tester and got a reading of 50. So it appears as if the pump is ok, the OPS is ok and everything in that dept is ok. Checked the fuse for the instrusment cluster ans that is ok. SOOOO, can anyone tell me what could be wrong? No oil pressure reading into the gauge in the cluster. Obivously an electrical prob, but what? Took the cluster apart from the dash and everything appears intact. I am trying to give all the info I can think of that would be helpful. Please please please....someone help. I REALLY DONT want to take back to stealership!