I dont know where their is a crankshaft under the seat

There should be an electrical connector under the seat.

yes you have to drop tank to replace fuel pump and filter as it is one unit pretty easy though.

crankshaft sensor is either under the harmonic balancer pully or bolted to block facing it you normally have to pull pully to change sensor but some you dont you will need a puller and a installer if you have to pull the pully

relay should be under the hood in relay area

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Could be the connector that is under the seat or a wire under there that has been cut with the seat movement. If you can swop the switches over it will rule that out, Dont know about the fuse but there is only the 2 fuse boxes anyway so quite easy to find one thats blown if its that. If not the wire, fuse or switch then you will know its the motor.

I think it is under the front seat. Not positive, but I had a couple of Toyota Vans, and the Previa was under the seat.

UNDER THE FRONT BUMPER

It is on the top of your valve cover.....look for the screw on cap:

Weak power from alternator.

Use a volt meter and check for the voltage.

It should be 13.8V to 14.2V

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Here's a quick check list for most common cost of SRS / Air bag problem.

Dirty contacts on driver and passenger seat belt buckles

Dirty contacts on seat belt connectors (under seats)

Dirty contacts on driver and passenger sides weight sensors (under seat)

Seat covers

Weight on passenger seat
(Example: grocery package trigger SRS / Air Bag light on the way home.)

I recommend you to pass an vacuum over the contacts and use CRC electronic parts cleaner to rule out connectivity problem.

I DO NOT recommend disconnecting the negative battery connector to clean the code(s).

Without the code(s) the dealer will takes "BILLABLE" time to reproduce the problem.

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Cheers,

Mustgo

there is a orange wire on the seat connector. follow it under the floor mat just under where you put your feet down . that gets corroded and breaks loose. fixed mine twice in 10 years and still working

have you checked the fuses / you can check for any burnt fuses concerning the seats. The "crank" I don't know what it is unless it is concerning the crankshaft/or crankshaft sensor.that has nothing to do with the seats though. some seat adjusters are electrical some are not. the ones that are not electrical, have either a bar under the seat or on the side of the seat to move the seat back and forth or adjust the back of the seat.

try looking underneath the seat on the passenger side. i own an older ram, but i found my jack there secured with a rubber strap.