Fuel Pump Circuit 1999 Rx300 Lexus

Lexus RX300

Does my 1999 rx300 have a oil pressure switch or a fuel cut off switch?

Before my car died I had to turn the key on and off really fast to get it to crank. Then I noticed the gas gauge was not working right. Then my gas tank was on E and I was trying to get to the gas station. While driving my car didn’t sputter out it just shut off and it wouldn’t start. My friend went and got some gas and brought it back. I thought I should wait at least 5-10 min before starting the car and not being a mechanic I ignored that and my friend spent 10min trying to start the car. It was totally dead. It wouldn’t even crank or turn. I replaced the starter and checked the fuses. I replaced the main fuse that was burnt. The oil level was super low and had been for awhile (i didnt know—-long different story). I put in oil then replaced the fuel pump. When I removed the fuel pump I noticed my gas tank was more than half full so I knew I hadn’t run out of gas. It cranked but didn’t start. Checked fuel pump circuit wires. Dead. Now I’m not sure

Fuel Pump Circuit

Sounds like you have yourself a good one here. I will say you are doing a great job so far in diagnosing the problem. Let me add a spin on the situation with the fuel pump. The fuel pump circuit wires will be dead when tested by yourself as the relay that sends the signal only sends power for a couple seconds unless the engine starts. So what does that mean? You will need two people to to test for power at the fuel pump connector. Have someone cycle the ignition key while you are underneath testing. This will confirm your suspicions.

Should you confirm that no positive and or negative is getting to the fuel pump then you will need to examine the rest of the circuit. Check to and from the fuel pump relay and then to ECM/Fuse. That being said, I do not see a fuel shut off switch like on Ford vehicles nor a oil shutoff switch. Use the wiring diagram to gain a better idea of the relays and fuses involved.

1999 Lexus RX300 Fuel Pump Wiring Diagram

A great tool for testing circuits is the Power Probe. You connect to both battery positive and negative with a cord. On the other end is a handheld tester with a Probe sticking out. The Power Probe give you the ability to send positive or negative battery voltage through the Probe with the push of a button. Now for the best part. The Power Probe has a built in circuit breaker that prevents you from blowing fuses or damaging components. I have used mine for years without disappointment. I looked one up for you. As an Amazon Associate I earn from qualifying purchases.