Cadillac Repair: Electrical/fueling/ignition!, oil pressure switch, fuel pump relay

Question
QUESTION: I have a 96 deville and the problem i have is something electrical that i cant figure out. driving home from work one day and car just died...thought it was my fuel pump cuzz i didnt hear it,i always listen for my fuel pump.So i had it changed out with a brand new one and the mechanic told me he took it for a test spin and it did it again,just died. so he told me its something in the wiring,short circuit or something...He claimed to fix it but a week later.....IT HAPPENED AGAIN! Died on me and I dont hear the pump. I tired of spending all this money and i know its probably something simple I just cant figure it out. I getting codes like service electrical system,service ignition system. Oh by the way the stock fuel pump that i thought went bad is perfectly good. Just something electrical. I love this car and dont want to lose it cuzz of something simple to fix....Can some1 give me some suggestions....Thank you.

ANSWER: You either have a problem at the rear electrical connector for the fuel pump at the fuel tank.

Or a problem with the oil pressure switch which controls the electrical current from the computer thru the oil pressure switch to the fuel pump relay and then back to the pump.

What you are going to need is electrical schematics (pictures) of where these components are located and how to test them and perform a diagnosis to find the faulty component.

Since pictures are NOT allowed on this person's website, you will need to e-mail: onlineautohelp@msn.com for these pictures and simple directives to find your fulty component.

---------- FOLLOW-UP ----------

QUESTION: You're the expert and I really appreciate ur help. Been trying to figure this out for so long. So you say it might be the oil pressure switch. I know you explained what its purpose is, but that would keep the fuel pump from not working??? Oil pressure?? I dont get it.

Answer
When you first turn ON the ignition key the computer energizes the fuel pump relay to run the fuel pump for 2 seconds to charge the fuel line just prior to your starting the engine.

Once the engine starts the computer redirects the fuel pump voltage down to the oil pressure switch which is now CLOSED because the engine is running and you have oil pressure. Thus the second switch in the oil pressure switch closes and sends voltage back to the fuel pump.

You can get an electrical schematic from: onlineautohelp@msn.com.