1999 Jeep Grand Cherokee Fuel Pump Relay

1999 JEEP GRAND CHEROKEE
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REDNEX18
  • MEMBER
  • 9 POSTS
i just recently did the bypass thing on relay for the fuel pump because 85 terminal is not getting power so its a short some were but its hooked straight to battery and works and runs fine. now to run the fuel pump i have a switch to turn it on and off but when i shut the switch off and key it stays running and spits and sputters then finnaly shutsdown any way i can get it to just shut off with key like normal the wire i have running from the line on the fuel pump is in terminal 30 to make the pump run
Oct 3, 2012 at 4:56 PM
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KASEKENNY
  • ✓Experienced Mechanic
  • 18,907 POSTS
I am attaching the wiring diagram for this because the feed for the power of the relay does not come direct from the battery. If you don't have power to the B+ terminal of the relay which in this wiring diagram is D2 then you have a fuse issue.

However, if you have no power coming from the PCM on D6 then you have a PCM issue.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

You do not want to bypass this relay because the PCM needs to be able to have the ability to cut the pump off because if you are in an accident and the fuel pump keeps running then it can turn a bad situation to a fatal situation.

Please see the wiring diagrams below and let us know if you need more help figuring out why you have no power to the relay.

Thanks
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Nov 28, 2021 at 8:26 AM

Suggested Repair

Do not leave the fuel pump relay bypassed. Check the fuse feeding relay terminal D2 (B+), and check for PCM control power on D6. Restore the factory relay circuit so the PCM can shut the pump off with the key and in a crash.

Conversation Summary

The owner of a 1999 Jeep Grand Cherokee bypassed the fuel pump relay because terminal 85 had no power, wiring the pump to the battery through a switch on terminal 30. The engine then continues to run, sputter, and shut down after the switch and key are turned off. The expert says relay power does not come directly from the battery: no power at D2 points to a fuse, and no power from the PCM on D6 points to a PCM issue. The relay should not be bypassed because the PCM must be able to cut the pump off for safety.

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