SAM65IAM

When driving above 70mph the oil light comes on and the guage slams in the corner to zero pressure. There is always sufficient oil in the vehicle and the engine temp is in the normal range. The dealer said there may be a wire harness problem that needs to be replaced for over $1,000. Already replaced the oil sending unit. Need your help in determining if I can replace only the wires affecting the oil pressure/guage instead of the complete wire harness.

MyMBbaby

Since, your issue is affecting the major component of electrical system in your car it is important to replace the complete wire harness.

Always remember that this complete wire harness includes all the essential wiring connections of your car.

You would rather cost something and use your car in it's top condition.

eddie a

You wont have to replace the complete wiring harness, all you have to check is the harness that connects the starter, alternator , oil preasure sensor, etc etc. It is called the positive cable, new at the dealer is around $220 you might find a used on in great condition on ebay for $80..

e reyes

Did you solve that problem cause i am having the same i replace the lower harnes, oil pressure sending unit, oil level sending unit, alternator and the oil tubes in the valve lifters and oil filter check valve. The red light keeps coming oil pressure drop to zero driving at more than 60 miles or at idle at 3000 rpm just need to replace oil pump any help thanks

1992 500SEL

SAM65IAM

My problem went away when I replaced catalytic converter.

e reyes

What was wrong with the catalytic ?
What efect the cat has in oil pressure?

SAM65IAM

I don't know what affect the catalytic converter had on the oil pressure. I had a problem passing my annual state (GA) emissions test. My service shop performed tune up and made adjustments to have the engine run better to produce cleaner emissions. It was discovered that my catalytic converter had totally collapsed. After replacing the catalytic converter, the oil pressure light and gauge problem disappeared. This has been 11 month ago. For more discussion email me at sam@jps-online.com.

e reyes

I am going to delete the cat and see if the oil pressure malfunction corrects .

and then replace the cat ill keep you posted thank sam65iam.

e reyes

well I fixed the problem it was the serpentine belt tensioner the belt sliping was doing the problem due to low voltage output ........