A friend has a 2005 explorer. Fuel pump 20a fuse blew. Replaced it and drove for 2 weeks with no issues. Now the fuse blows when he turns the key. If we remove the fuel pump driver module and turn the key, it doesn't blow. If we put jumpers across the pins on the the driver module connector, fuse blows. If we connect the driver module and unplug fuel pump electrical connector, fues does not blow. If we test the fuel pump wiring harness, we get 0 .7 ohms. Are we safe in thinking the pump is bad, or are we missing something?

 

With the testing you've done, I'd say you've pretty well narrowed the culprit down to the fuel pump or the wiring between the driver module and the pump. Do you have a fused test lead that you can use to attempt to power up the fuel pump to see if it blows that fuse? Or an old-school test light to see if, when connected in series with the fuel pump, the test light glows at full intensity?

-Rod

 

can you explain this a little more? We did test voltage at the connector to the fuel pump. When we turned the key on, we had 12V. Im trying to find something that we can connect to the connector to test a load. And possibly hooking up a battery to the pump with a fuse and see if it blows.

 

If you insert a test light in series with a load, the brightness of the light is determined by how much current the load is drawing. This is a way to locate shorts without blowing a bunch of fuses. One way to do it is to essentially replace the fuse with a test light. If the short/excessive load is still present, the test light will glow at nearly full intensity. Once the short/excessive load is removed, the brightness of the bulb will reduce drastically. You kind of did this by measuring the resistance of the fuel pump harness at 0.7 ohms, although the fuel pump is an inductive load so it's difficult to say whether that by itself would blow the 20 amp fuse. If the battery were at 12.5V a 0.7A load would draw just under 18 amps, so that's pretty close to 20 amps, but since it's a motor it's tough to say what the real draw is when power is applied.

-Rod

 

So my buddy took a chance and bought a new pump. I was hoping we could have done some more testing first. But he felt confident enough that it was the pump. Well he got everything all back together tonight, including a new fuel filter. And it fired up. No blown fuse when the key was turned. Needless to say, he is a happy guy. Thanks for your help Rod.

 

You're welcome, and I'm glad to hear the issue seems to be resolved!

-Rod

 

What number fuse is it?
It's showing that I have negitive gas in my truck and the low fuel light comes on but it runs fine and has a full tank, put in a fuse it started working again then i touched some wires now its out, any ideas?

 

Is your Explorer also a 2005? Which engine does your Explorer have? In the 2005 4.0L V6, the fuel gauge is powered by the Battery Saver Relay fuse, F2.18 (10A). There are a lot of different circuits on that fuse, so it's difficult to suggest what wires you might have touched that caused the fuse to blow away. Do you know what you touched that correlated with the fuse blowing, or at least the general area the wires went to?

If you have the 4.6L V8, then the fuel gauge is powered directly via the instrument cluster via fuse F2.15 (5A) which appears to only power the instrument cluster and the rear wiper motor assembly microprocessor.

-Rod