When I get a few minutes i will go through the wiring diagram again. But on my 98 I know the oil pressure sensor is in the fuel pump circuit.
I believe its wired parallel to the fuel pump relay.
It is my belief that computer starts the fuel pump to get the engine started until oil pressure is established. At that point the oil sender is powering the fuel pump. If i were to loose oil pressure, I would be very happy if the fuel pump was shut down.

It wouldnt be the first time i was wrong.

Daddysblazer - Im sorry if I offended you in anyway. But I do appreciate you editing your original post.

 

Power is provided to the fuel pump by the ECM B fuse in the underhood fuse/relay center which ties in with both the fuel pump relay & the oil pressure switch side of the oil pressure sending unit. Power to the pump is provided through a parallel path via the oil pressure switch and the fuel pump relay whenever the key is on & the engine is running.

And Daddysblazer, I'm not sure where the attitude came from, but you need to calm down. It takes a VERY shady dealership/mechanic to do what you have suggested and it is FAR from typical. That's all that was said, nothing to get your drawers in a twist over...

 

^^ I'm not good with wiring diagrams or schematics, but I do know that you can start and drive the truck with it unplugged.

Feel free to try it, right behind the distributor you'll find the oil pressure sendind unit, crank truck up, unplug, and truck continues to run..

 

Nothing I have stated disagrees with that.

 

I guess I over reacted and I apologize. But I wasnt trying to argue with anyone I was meerly making a suggestion to someone and I felt like I was attacked. I really enjoy this website and I dont come here to argue just share Information and basically (TALK TRUCKS) if you will again sorry

 

I agree that's how i think of it what a nice way of letting it out

*thumbs up*

 

Okay Daddy,

I thank you any way and everyone else for your helpful input.
I drive a Mazda too and i love it!! What a car!! Too bad I have to run the wheels off chasing after parts for the Chevy.
I must say that i am going to enjoy getting that blasted old fuel pump out of that troublesome Blazer. I have a 14 lb hammer and a solid concrete front step that is awaiting its arrival!

 

i had problem wit my fuel pump twice along long time ago.too.i found out there was a recall on these blazers that i guess no one new about.bought one from advance put it on and didnt last a week.took it back and talked to someone bout pump and he told me there was once a recall on blazer harness.sure enough he looked at connections in the pump and it was burned out.he gave me another one wit brand new harness and it comes wit instructions on how to color match.its easy.i payed almost 300.00 then.and havent had problems at all.i even replaced fuse in box,didnt work.hope this helps

 

oh,forgot mine is a 99.

 

No matter, 98 0r 99. Some 99's had extra features in the cab, some didn't. I replaced the pump over a year ago but used the old harness. The truck is still running, and running well. Then I later helped replace another pump in a friends 99. I'm an expert now!
I have no doubt the wiring is faulty in these vehicles. I get worried when my blinker relay starts clicking for no reason. This even after I thought I had fixed it by replacing the multi switch(left lever on treering wheel). The muti switch does the signals, wipers, high/low beam and cruise control. It is a cheap plastic thing but not cheap to buy and,.... it is stupid!