Why would a relay not work on fuel pump - 2001 Daewoo Lanos

1. Check the fuel pump fuse: Locate your vehicle's fuse box (usually found under the dashboard or in the engine compartment) and check the fuel pump fuse. If it is blown, replace it with a fuse of the same amperage. If the fuse is fine, proceed to the next step.

2. Check the fuel pump relay: The relay controls the power supply to the fuel pump. You can typically find the fuel pump relay in the fuse box or a separate relay box. To test the relay, you can swap it with an identical relay (such as the horn relay) and see if the fuel pump starts working. If it does, the relay is the problem and needs to be replaced.

3. Inspect the wiring: Damaged or corroded wiring can cause a loss of power to the fuel pump. Check the wiring leading to the fuel pump for any visible damage, corrosion, or loose connections. Repair or replace any damaged wires and clean corroded connections.

4. Test the fuel pump for proper function: If you have access to a multimeter or test light, you can test the fuel pump terminals for power when the ignition is turned on. You should see a voltage for a few seconds as the pump primes. If there's no power at the terminals, the problem could be a faulty ignition switch, fuel pump control module, or a wiring issue.

5. Faulty fuel pump: If all the above steps show that power is reaching the fuel pump, but it is still not working, the pump itself might be faulty and need replacement.

Switch the horn relay with the c/op relay to see if it’s the relay. I don’t know why they have to give u complicated answers.

I just looked at a wiring diagram of the fuel controls for this model: there is no fuel shut-off switch in the wiring. It's pretty straight forward, typical fuel pump controls: the fuel pump relay is in the under-hood power distribution center. When this relay is turned on, power is sent to the fuel pump, nothing else is in the path of the hot wire to the pump module so it (the pump) should be working.

So if pump is not on, you can diagnose the wiring right here at the fuel pump relay. First you verify the power feed for the pump is available at the relay. (One terminal at the relay will have battery voltage with key off. If you pull the relay out and use a test light, one terminal position will be hot.) Next you verify the relay is working, sending power to the fuel pump in the gas tank. You do this by having someone cycle the key to on, while you hold a finger on the relay (it's back in place) to feel it click on. You should feel it, maybe even hear it, the relay will energize every time the key is turned to on, and this is what sends power to the fuel pump.` If it all works, and the pump is not on, the pump probably needs replacing. If the pump relay is not clicking on, that's a wiring hassle, including the wire to the engine computer. The pcm is what controls the relay turning on.
Do you know if the fuel pump has ever been replaced in the car? If it is original, it has been a good long run.

Probably a relay, not a fuse. If there is a fuse it will be marked on the fuse box panel. Usually the relay is located under the hood either in a fuse/relay box or on a rack of several relay on the firewall.

Either the fuel pump is not working, or the filter is totally blocked.
The fuel pump circuit needs checked to see if it's a wiring problem or a failed fuel pump. There will be (probably) a fuel pump fuse in your fuse block, and a fuel pump relay under the hood.
If you check the fuel pump wire for power at the gas tank connector while the engine is cranking over, and there is power there, and the ground for the pump is good, then the pump is not working and will have to be replaced. If you do not have power when cranking, the wiring at the fuel pump relay will have to be checked. Simple relay- has a power feed for the pump at one relay terminal (it is hot at all times), and a fuel pump wire to pump on another terminal (the power out for relay). When relay coil side is energized from a signal from computer, the relay contacts close and power is sent to the pump. The other relay terminal is a ground for the coil side of relay. Pull the relay out and you will see the diagram etched on it. If there is a fifth terminal, that could be a pump prime terminal, or a way to keep the pump running when engine is running through the oil pressure switch. But when cranking the engine, the computer will signal the relay to send power to the pump.

Hi and welcome to FixYa!
The fuel pump relay regulates the power given to the fuel pump. If the fuel pump relay is faulty there will be no power to the fuel pump and will result to fuel supply failure. These relays just like the others serves as regulators so that the battery will not fail during electrical loads.

Hope this helps and thank you for using FixYa! Have a good one!

The fuel pump relay needs to be working to turn on the fuel pump. The fuel pump relay is behind the firewall of the battery. To confirm it is bad, pull off the relay and jump the wire at # 7 and #8 to energize the fuel pump. If it works then replace the relay. Good luck.

first you need to test your wires going back yo the fuel pump inorder to see if you have a bad wire or not.. does the fuel pump initilize upon turn ignition on . if yes then you need to chk possible spark issuie . if no initilize then test connector at the fuel pump and work your way back to the fuel relay swtch and if that tests out work your way back to ignition switch . ( s/b only 1 relay )

fuel filter? how about power to the fuel pump,loose ground wire to chasis? wiring harness? terminals clean at point of connection?did you check the fuel pump relay? Relay is located in electrical center under the hood on the driver side.relay and fuse legend will be on bottom side of cover, you sould be able to switch with another relay that you know works, ie: switch horn relay with fuel pump relay, honk horn to insure both relays are working when either relay is inserted into horn slot. Do you by chance have the electrical schematic drawing for the fuel pump?

Personally I wouldnt bother tracing the wire as it is probably not worth your time, and just run a constant 12v from the battery to the relay on like 10ga wire. There is probably a short somewhere in the system which can be a real headache to find.

Also it may sound dumb, but check your fuses, and the fusible links under the hood. Chances are that they are all fine though, especially if you have dash lights.