Electric Seat Blowing Fuse

[TXFishin]

I have a 2012 Ford Expedition EL Limited 4X4

The 40amp fuse for the drivers side seat will randomly blow

I pulled the seat to check for any obstructions in the track or worm gears, all seems fine.

I ran the seat in all directions for several minutes and the electric motors stayed cool to hit touch, didn't even warm up

Cleaned and lubed everything, checked and cleaned all the connectors, put it all back and still doing the same thing.

It doesn't matter if you are sitting in the seat or not.

Does anyone have any suggestions on possible causes or troubleshooting?

Regards

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[1955moose]

I ran into the same thing on my 2000 Expedition about 6 months back. I did like you, checking for obstructions, the whole 9 yards. Turns out the fuses from the dealer were garbage. I ordered 5 used Ford ones from a guy on eBay . I'm guessing the year of the fuses was 2000 or so, popped one in, hasn't blown since. Don't know why the dealer ones kept blowing. You might try the maxi fuses from O'Reilly or Auto Zone, or do like I did and find some used ones on eBay, or wrecking yards.

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[TXFishin]

I ran into the same thing on my 2000 Expedition about 6 months back. I did like you, checking for obstructions, the whole 9 yards. Turns out the fuses from the dealer were garbage. I ordered 5 used Ford ones from a guy on eBay . I'm guessing the year of the fuses was 2000 or so, popped one in, hasn't blown since. Don't know why the dealer ones kept blowing. You might try the maxi fuses from O'Reilly or Auto Zone, or do like I did and find some used ones on eBay, or wrecking yards.

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I've gone thru probably a dozen fuses, various brands, AutoZone, O'rielys, eBay, etc

Some will blow immediately when I open the car and the seat "auto-adjusts" for easier entry, other times it may make it a day. Once and only once it lasted about 2 months

I thought it had something to do with the outside temperature as it started to happen when it was cold out, thinking the cold weather might have solidified some grease in the tracks or screw adjustments, that's when I took the seat out and checked everything.

I thought about going up to a 45amp, but didn't think the extra 5 amps would be a good idea

I've also thought about wiring in a 40amp re-setable breaker due to the cost of the fuses, but haven't gotten around to that yet

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[stamp11127]

For what we are dealing with temp doesn't matter to fuses. The only thing that does is the amount of current though the circuit. To pop a 40 amp immediately usually indicates a dead short. That can be in the harness or motor, easiest way to check would be to place the seat in the position you want then disconnect the motor. If fuses keep blowing then it isn't the motor. Time to get the diagrams out and trace the circuit in that case.
Increasing fuse rating moves the weakest link to a different component. That could be wiring or a different component. Fire risk is increased since you don't know what will fail. Play it safe and stay with the rated fuse for all circuits.

 

[1955moose]

Did you or a shop work on the inside of vehicle lately? I'm with Stamp, you never increase fuse size. Wiring will overheat and catch fire. Start with the automatic seat switch, that moves seat to set position. You definitely have a dead short. Finding it is where the fun starts. After that switch, look real carefully at the wires going to the 3 motors, insulation may be worn on a hot wire, touching against metal. Lastly, you might want to replace the power seat control module. It could be shorted out.

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[TXFishin]

Did you or a shop work on the inside of vehicle lately? I'm with Stamp, you never increase fuse size. Wiring will overheat and catch fire. Start with the automatic seat switch, that moves seat to set position. You definitely have a dead short. Finding it is where the fun starts. After that switch, look real carefully at the wires going to the 3 motors, insulation may be worn on a hot wire, touching against metal. Lastly, you might want to replace the power seat control module. It could be shorted out.

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I was considering the switches as a possibility, would the drivers side be compatible with the passenger side, so I could swap them to see if the problem moves?

I was also wondering if it could be a bad relay not making good contact at times.

It does seem like the seatback tilt blows the fuse more than any other. I say this because I've had it work for a day or so, and went to tilt the seat back and the fuse blew. However, it is not consistent at all, still blows when you use other functions, it just seems more consistent with the seatback tilt.

Also, when I pulled the seat, as part of the troubleshooting, I inspected the wiring to see if there may have been some insulation worn or had be caught in the track some how, but all that looked fine, however, having dealt with wiring issues on other cars, boats and airplanes, perfect insulation doesn't mean perfect wiring, and it can definitely be a pain to locate the issue, especially if it's somewhat intermittent.

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[TXFishin]

For what we are dealing with temp doesn't matter to fuses.

I was only thinking temperature because if the previous owner used the wrong oil/grease, the viscosity could go up in colder weather and place more drag on the slides as worm/screws. I've seen oils and grasses get very thick, even sticky, when used in incorrect applications and cold temperatures


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[1955moose]

If the seat is moving normal and not slow before blowing fuse, I don't see grease being an issue. I don't know about the newer models like yours, but on my 2000, it uses a 30 amp maxi fuse for driver's seat, and power pedals. Yours is 10 amps higher. Do you have dual power seats? Are you going to continue with the diagnostic? Or is a shop going to finish troubleshooting? Your going to need a 2012 wiring book, and a bit of diagnostic experience.

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[stamp11127]

The memory switch is a 2 pole version wired on the ground side. All it does is provide a ground signal to "Mem Recall 1" and "Mem Recall 2" pins on the Driver Seat Module.
The other switch also provides input to the driver seat module. The DSM also controls the memory mirrors so do not rule them out just yet.

The highest fuse used is 30amp in location F74

Disconnect the recline motor and see if the fuse still blows.

 

[TXFishin]

If the seat is moving normal and not slow before blowing fuse, I don't see grease being an issue. I don't know about the newer models like yours, but on my 2000, it uses a 30 amp maxi fuse for driver's seat, and power pedals. Yours is 10 amps higher. Do you have dual power seats? Are you going to continue with the diagnostic? Or is a shop going to finish troubleshooting? Your going to need a 2012 wiring book, and a bit of diagnostic experience.

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Troubleshooting this on my own.

Maybe the previous owner the fuse to 40amp because of the issue, I need to check what it should be.

Yes on the dual electric seats

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