1. Autos
Send to a Friend via Email

Your suggestion is on its way!

An email with a link to:

http://autorepair.about.com/library/a/1d/bl955d.htm

was emailed to:

Thanks for sharing About.com with others!

Questions and Answers

Jeep Cherokee Fuel Pump Power

Q. Hi Vincent, I have a question. I hope you can help and I appreciate the post on the fuel pump replacement. I changed mine last night. It worked great for a while but now there is no power going to the fuel pump. Here is what I have done. First I changed the relay in the fuse box with new one. Checked the fuse, replaced the fuel filter and last night the fuel pump.

Jeep Cherokee Fuel Pump Power

I figure the only thing left could be the fuel sending unit or a short somewhere in the wiring. However, I don't know much about electronics. If it was a short would it ever get power? I just don't want to replace the fuel sending unit only to find out it has something wrong in the wiring.

Also, is a fuel sending unit something you can get at an auto parts store or is that a dealer item. If it is a dealer item, is getting a used one from a salvage yard a bad thing? I have a 1996 Jeep Cherokee 4.0 liter.

Thanks,
Rob

A. I don't think it's a fuel tank sending unit. All that does is tell the fuel gauge how much fuel is in the fuel tank. It doesn't have anything to do with the fuel pump.

I think the problem is most likely the Auto Shut Down relay. Here's how to test it:

Jeep Cherokee Fuel Pump Power
  1. Remove relay from connector before testing.
  2. With the relay removed from the vehicle, use an ohmmeter to check the resistance between terminals 85 and 86. The resistance should be between 75 +/- 5 ohms.
  3. Connect the ohmmeter between terminals 30 and 87A. The ohmmeter should show continuity between terminals 30 and 87A.
  4. Connect the ohmmeter between terminals 87 and 30. The ohmmeter should not show continuity at this time.
  5. Connect one end of a jumper wire (16 gauge or smaller) to relay terminal 85. Connect the other end of the jumper wire to the ground side of a 12 volt power source.
  6. Connect one end of another jumper wire (16 gauge or smaller) to the power side of the 12 volt power source. Do not attach the other end of the jumper wire to the relay at this time. WARNING: Do not allow ohmmeter to contact terminals 85 or 86 during this test.
  7. Attach the other end of the jumper wire to relay terminal 86. This activates the relay. The ohmmeter should now show continuity between relay terminals 87 and 30. The ohmmeter should not show continuity between relay terminals 87A and 30.
  8. Disconnect jumper wires.
  9. Replace the relay if it did not pass the continuity and resistance tests. If the relay passed the tests, it operates properly. Check the remainder of the ASD and fuel pump relay circuits.

I think that should do it for you.

Jeep Cherokee Fuel Pump Power

Additional Information provided courtesy of ALLDATA

Back to Index
You can opt-out at any time. Please refer to our privacy policy for contact information.

©2014 About.com. All rights reserved.