2004 Sport Trac Fuel Pump Shut-Off Switch Malfunctioning In Rain

[evolross]

I bought my Sport Trac brand new in 2004. It's always ran really well. Starting around 2007, every once in a while my fuel pump shut-off switch would trip for no reason. Usually maybe once every six months or so. It happened so rarely that I kept forgetting to have it serviced or looked at. I noticed it also ONLY ever happened on really, really rainy drives. Like torrential downpour. So I would pull over, reset the button, and be on my way. Sometimes it would continue to happen on the same drive, especially if it were still raining. So it might happen two or three times on a single rainy drive, then it wouldn't happen for another six months. Also, sometimes when it happens I get the check engine light and a "Check Gauges" message on the odometer. Sometimes I don't get these messages. If the check engine light comes on. It goes off by the next day. I've never taken it to get checked for the code because it's usually off by the time I could get to a dealer or an Auto Zone.

So this last weekend I drove from Ohio to Virginia, about 10 hours. I was in torrential rain the whole way and it tripped about 10 times on the way there. Each time, I had to pull over, reset it, and keep going. Sometimes the engine would stay on for 2 or 3 hours after a trip, other times it would trip 5 minutes after the last trip. Once I got to Virginia, it didn't trip the entire weekend, even on 30 minute drives or so. But then the whole way back, it happened again, probably 10 to 15 times. And it WASN'T rainy when it started happening.

This was a major inconvenience and I definitely need to get this looked at as I have a lot of drives for work coming up. I think it's the wiring or something as everything else seems to be working properly. Has anyone on here seen anything like this with their vehicle?

I called the dealer and they acted like it could be really difficult to diagnose if they couldn't cause it to happen while the car was in their possession. Which is a bummer because it rarely happens, unless it's raining. Even then, it sometimes doesn't happen. The only guarantee is that it usually KEEPS happening on the same drive once it happens the first time. This makes me think it has something to do with getting wet or getting hot or something like that.

I've been researching this and I wanted to add that the reset button on my Sport Trac doesn't "stay down" after I push it in. It's just a button that you can depress then it pops back up. It works in resetting the fuel-pump, but it doesn't stay "depressed". This is normal right? I'm thinking it is, since it successfully resets the fuel pump and I can keep driving (until the next faulty tripping of the switch).

[evolross]

I remembered yesterday that this problem has only really ever occurred with passengers in the car with me. Anytime I can remember it happening, it happened with someone in the passenger seat.

So last night I picked up my brother-in-law and we went driving around and I had him move his feet around by the reset switch (which is under the glove compartment down by the floorboard). Sure enough, every time he bumped it with his foot, the car shut down! We tested it several times and even drove around for 20 minutes without it tripping. But as soon as he wiggled the switch and its wires, it would trip. So I guess the whole idea of it only happening in the rain was in my head. This would also explain why it happens so randomly. It's the passenger bumping the wires and/or the switch.

So I looked at the switch and saw the two wires coming from it and where they connect to the switch is really loose. In saying "loose" I mean that it has a lot of wiggle room. I think one of my friends may have kicked it really hard while riding or something and maybe loosened something up.

I noticed that when I unplugged the wires and their harness from the switch, it would cause the switch to trip and shut the car off. So it must trip if it gets disconnected.

Does anyone know how much it is to replace the switch and/or the wires and/or the harness? I'm not sure exactly what the problem is or which part has the problem. Any experience with this?

[ncranchero]

Obviously a defective inertia switch. When you depress the red button it should stay down. I've never personally seen a bad one and I would think you would be safe in picking one up at a salvage yard. A new one should run around $20-$25.

[BroncoJoe19]

I agree.. definitly a bad switch. Another member had a similar problem with his bronco. He swapped out the switch.

Electrical wouldn't trip it as it is trigered by movement, like a crash.

[RayMoyer]

um... just because u have a problem with you cut off switch doesnt mean its bad...

gesh...

1 u said u usually had a passenger when it happens
This used to happen to me, they would kick my switch and set it off
2 there was a recall
there was a recall on ST fuel pumps awhile back, i had mine swapped out and havent had a problem sense.