Oil light sometimes flickers on and it's not because of the usual reasons

My oil light flickers on and off (sometimes stays on solid) when idling, after the engine has been running at normal operating temperature for more than 15 minutes. Swapped out the oil pressure switch with an oem switch from the dealer, still had the problem.

I had the mechanic do a pressure check and the pressure checked out at 1000 rpm (or maybe it was idle, I forgot what he said, but I do know he followed the proper steps for sure) and at 2500 rpm. He also dropped the oil pan and looked around for any wear and tear, he found nothing wrong. So my oil pump is working and screen was not clogged. I also mentioned to him to when I dropped off the car that the bearings might also cause the problem, as I read this in other posts. So he knew to look for that too.

Because everything checked out, my mechanic said that the problem could be caused by a bad wire on the electrical connector that connects to the oil pressure switch. He told me that problem is usually with cars made by Dodge/Chrysler, and this is how he fixes the problem with the same situation; so, this might fix my car's problem. He said that the hot engine oil and worn out wire are effecting the signal. My mechanic told me to get a new electrical connector at the dealer so he can pigtail it on. Does anyone know or think this could be the actual problem and solution?

180,000 miles on the car

Does the operation of the light seem to behave any differently shortly following an oil and filter change? What weight of oil are you using?

-Rod

Last time I got an oil change, I don't remember it happening right after. I think it started to happen a few weeks down the road. My next oil change is coming up, so maybe I should wait then on replacing the connector/wire, until after the oil change... Then I could double make sure that the oil light doesn't behave differently right after an oil change.

I take my car to the dealer for an oil change because I like to use Motorcraft filters and oil. I use to change it myself, but my new apartment doesn't allow maintenance on cars to be done, especially when dealing with fluids and car raised on jacks. The dealer now puts in 5w-20 because Ford back spec'd the oil from 5w-30 to 5w-20 in one of their TSBs. The tecs said it works just as good as 5w-30 and gives like 1-2 mpg more, so Ford made the change to 5w-20.

I do know that a couple months ago my oil light would just come on when idling on a hill at a stop light. A few weeks ago, the light started to come on when idling anywhere on flat ground: stop lights, stop signs, stuck in traffic. After replacing the switch, the light now flickers on and off when idling after driving the car for a while.

So the light only flickers and/or comes on when the vehicle is idling, you haven't seen it on when the car is moving or the engine speed is above idle speed? If that's the case, I don't really think the wiring would be the issue since the wiring would be moving and getting tugged more during driving than when stopped at idle. It would be interesting to have the shop temporarily install a t-fitting so you could have your pressure switch installed at the same time as a mechanical oil pressure gauge, then see what the pressure is reading when the light is flickering.

-Rod

That's a pretty good idea Rod, thanks. I should look at having the mechanic do that sometime for me, to see for myself what the pressure is when the light is flickering. The mechanic told me he noticed the valve cover gasket was leaking while he had the car. I think I might just have him fix that for me pretty soon (I looked around the engine and saw what looked like a tiny bit of black grime and dirt near a corner of the valve cover, so it might have a small leak), I'll talk to him about installing an oil pressure gauge and see what's up...

But yeah, the oil light doesn't come on at all when RPMs are above idle. My mechanic did tell me that if I buy the electrical connector at the dealer (he told me it should be like $15), he would pigtail it on for free.