J_White

OK so I have an 89 4.0 Cherokee I put a new fuel pump in when hooked up to the stock wiring it DOSE NOT WORK but if I hook it up straight to the battery it works I've checked relays fuses there all good I have no idea why it won't work when hooked up correctly any one had this problem or know what it could be

cruiser54

Have you checked for power at the plug?

oldguy52

Check under the rear seat. The wire harness running to the fuel pump is right there behind the driver. You or someone may have tossed something there that broke the wire. Good luck.

J_White

I've checked wires leading to the plug and when I crank the motor over I'm getting power checked with multi meter but no power when I just have the key to the on position

cruiser54

See if you have continuity across this with the key On. It's okay to bypass it.

Here

J_White

I have current to that I'd have to check again if I have going to both leads will it damage the fuel pump if I bypass it

cruiser54

Will do no damage at all.

J_White

Now correct me if I'm wrong but that turns the voltage from 12 to 9 voltage sorry if it's a dumb question wiring is not my cup of tea lol

cruiser54

Not a dumb question, and you are 100% correct.

J_White

OK I'll try jumping it tomorrow and let you know what happens

J_White

OK went to test the voltage to the wires for that resistor and now I'm not getting any voltage to it or to the fuel pump wiring in the car checked the relay and it's still good I'm lost lol

cruiser54

How did you check the relay?

J_White

I moved them around and have replaced the fuel pump relay

cruiser54

Do you have power to the #30 terminal of the relay socket?

djgrayxj

Note from DJ
Pete I’m taking the liberty of adding some clarification words to your question.
”With the key on” Do you have power to the #30 terminal of the relay socket?