89 4.0 auto 4x4 fuel pump not working

[SayBye]

I pulled my mj into the garage yesterday to pull the bed off and now the fuel pump won't come on.

 

I read where there's a ground behind the tail light, I don't see any evidence I ever had one of this truck.

 

I read where the relay is located, swapped them out with others from the rack, still nothing.

 

So number one is how to I check my voltage at my relay center? I was getting like 4.2v there yesterday but I'm not sure I was checking it right, however I was getting that same reading at the fuel pump disconnect.

 

I'm trying to find the resistor under the hood by the headlight relay? I read its white, does anyone have a picture of it because I'm just not seeing it.

 

I ran two wire from the batt. Straight to the fuel pump and it fires right up and the truck runs normal.

 

Where does the relay center get its voltage from? Thanks guys!

[HOrnbrod]

I pulled my mj into the garage yesterday to pull the bed off and now the fuel pump won't come on.

 

I read where there's a ground behind the tail light, I don't see any evidence I ever had one of this truck.

 

Unscrew and remove the left tail lamp from the fender. The ground connection is a sheet metal screw fastening several wires, including the fuel pump ground wire, to ground behind the lamp.

[Jeep Driver]

 

I pulled my mj into the garage yesterday to pull the bed off and now the fuel pump won't come on.

 

I read where there's a ground behind the tail light, I don't see any evidence I ever had one of this truck.

 

Unscrew and remove the left tail lamp from the fender. The ground connection is a sheet metal screw fastening several wires to ground behind the lamp.

 

This is the third OP recently that has removed the bed  and either have no tail lights/running lights working or no fuel pump. 

 

 

When I install the the new tail lights........that G107 ground will be direct to the battery. I already have a new ground post at the rear for trailer brakes and accessories.

[SayBye]

 

I pulled my mj into the garage yesterday to pull the bed off and now the fuel pump won't come on.

I read where there's a ground behind the tail light, I don't see any evidence I ever had one of this truck.

 

 

Unscrew and remove the left tail lamp from the fender. The ground connection is a sheet metal screw fastening several wires, including the fuel pump ground wire, to ground behind the lamp.

The bed skins were cut off by a PO and they were using it as a flat bed on the farm. So no tails light, all that was there was the bed floor.

[SayBye]

 

I pulled my mj into the garage yesterday to pull the bed off and now the fuel pump won't come on.

I read where there's a ground behind the tail light, I don't see any evidence I ever had one of this truck.

 

 

Unscrew and remove the left tail lamp from the fender. The ground connection is a sheet metal screw fastening several wires, including the fuel pump ground wire, to ground behind the lamp.

No tail lights or bed sides were on the truck when I got it but it ran fine til I pulled the bed off.

[fiatslug87]

The fuel pump resistor is on the driver side fender by the air box, at least for a 4.0L. I believe early models did not have it. PN is 33000682, bottom of the picture.

[HOrnbrod]

No tail lights or bed sides were on the truck when I got it but it ran fine til I pulled the bed off.

Then the fuel pump hot and/or ground wire has an air gap caused by whatever you removed. Follow the wires from the fuel pump and see where the break is.

 

BTW, what model/engine/etc. is/was the truck?

[SayBye]

 

No tail lights or bed sides were on the truck when I got it but it ran fine til I pulled the bed off.

 

Then the fuel pump hot and/or ground wire has an air gap caused by whatever you removed. Follow the wires from the fuel pump and see where the break is.

 

BTW, what model/engine/etc. is/was the truck?

It's an 89 4.0 auto 4x4.

[cruiser54]

 

 

No tail lights or bed sides were on the truck when I got it but it ran fine til I pulled the bed off.

Then the fuel pump hot and/or ground wire has an air gap caused by whatever you removed. Follow the wires from the fuel pump and see where the break is.

 

BTW, what model/engine/etc. is/was the truck?

It's an 89 4.0 auto 4x4.

 

Here's a good mod to address the grounding issue.

 

http://cruiser54.com/?p=249

[HOrnbrod]

To improve the craptastic left tail lamp ground, you can run an additional ground wire from the grounding screw behind the lamp down to a solid mounting point on the frame, like a bumper bolt.