Sitting in drivers seat kills truck..

[Skyr]

Ive been trying to trouble shot my cousins truck for the last month. But could never have it give me a problem. Its a 98 Mazda b3000 4x4 with the 4.0 l engine. It finally died on her enough to have it towed back to her apartment and Im still at a loss to figure to it out. Whenever someone sits in the driver seat it dies.. It runs GREAT until you sit down.. Any ideas here would be appreciated..

 

[scrapper]

drive standing up?

 

[RonD]

Not sure on the '98 but later models have a connector under the drivers seat, it goes thru the floor, 20 or 40 pins.

Look under the truck and see if you see it, it isn't small.

Problem was moisture getting in and causing intermittent problem.


But just sitting in the seat shouldn't cause the problem

 

[James86]

I thought B3000's were 3.0's and B4000's were 4.0's.... was the engine swapped at some point?

 

[Skyr]

it is the 4.0L engine...Couldn't find a plug in at all under the seat...... Its gonna drive me NUTZ!!!! And it is a B4000 Sorry...

 

[Skyr]

I found the plug and its alright.. I shook it wiggled it and all never bothered the truck.. Climbed up and sat down hard in the seat and truck died... I also started it back up rocked the heck outta the truck to make sure it wasn't just a loose connection somewhere else that's shutting it off and it didn't bother it... Is there any sensors built into the seat that could shut the truck off or I seen some wiring running up threw a grommet in the floor and under the seat(it comes from the same clip that was giving the other guy problems..)

 

[Mickey Bitsko]

I found the plug and its alright.. I shook it wiggled it and all never bothered the truck.. Climbed up and sat down hard in the seat and truck died... I also started it back up rocked the heck outta the truck to make sure it wasn't just a loose connection somewhere else that's shutting it off and it didn't bother it... Is there any sensors built into the seat that could shut the truck off or I seen some wiring running up threw a grommet in the floor and under the seat(it comes from the same clip that was giving the other guy problems..)

kind of obvious but, is it a power seat?

 

[saskbill]

Possible connections in the seat area would be seat belt closure sensor (runs the 'nag' light/buzzer to fasten your seatbelts), any power motors for a non-manual seat, and possibly seat warmer. If anything like this was shorting to ground when you sat down it could load the alternator and stall ya out.

Had this happen on my old ford half ton, sorta - would stall out when I hit the brakes, especially when it was wet out. Turned wiring for a missing/damaged trailer connector was partly contacting the rear bumper and grounding out the brake light circuit!

In my self defence, I had picked it up not too long before that, and it had several previous owners who hadn't exactly lavished care on it

 

[adsm08]

Start by figuring out what you are loosing to make it shut off. Are you loosing fuel, or spark? Once it dies will it restart? If not that should make this easy to find.

 

[RonD]

Reads like someone(previous owner) installed a kill switch, if that connector is OK, because there is nothing in the seat electrics that would cause the engine to die without blowing a, or some fuses, and it certainly wouldn't restart with blown fuses that killed the engine.

Most likely cuts fuel pump power since it is easy to get to from inertia switch in passenger footwell.

Look under the dash for a toggle or push button switch, sit in drivers seat(engine off, lol) and feel around, it should be accessible by driver to reactivate engine.

The fact it restarts when drivers seat is empty means factory electrics shouldn't be involved as shorts blow fuses.

As a long shot I would check to make sure there is a ground strap from engine head to firewall and both ends are tight, this is the cab, computer and instrument ground, if computer loses ground(power) engine will shut off.

 

[Skyr]

Manual seats in it...No heated seats...The wires I mentioned don't run to the seat(sorry if I was misunderstood) They just run thru the floor and under the drivers seat towards the middle...All of them seem to come from the clip that was giving RonD problems.. Her seat was loose at the start and I tightened it down again think it had a switch in it that made it think she was in a wreck. The grounds I already checked and they all looked and felt good..Gonna pull the seat outta it tomorrow and check that wiring harness that runs under it.. Im completely stumped here..Ill also check for a kill switch in it.. I doubt it has one as its completely stock and as far as I can tell always has been.. Thanks for the ideas.. Any other ideas would be greatly welcome also.. Oh and it restarts as soon as someone gets outta the seat..LOL.. Maybe the driving standing up idea is the best idea I can give her...lol

 

[black_demon69]

drive standing up?

or loose some weight lol

seriously you could try removing seat and sit on floor to see if problem goes away (could be a pinched wire)

 

[Mark_88]

The 96 I just tore apart had the main wire connector directly under the driver seat...it feeds all the lights, fuel tank, and whatever else is behind the driver seat (on the outside of the cab)...

Maybe get a new seat cause it sounds like the springs are shot in the one you have...and that plug under the seat (unless things changed in 98) may "appear" to be solid...but anyone who has had an older Ranger can attest to the plugs breaking down over time...to the point of causing intermittent then constant power outages...

So...check it good before moving on to other things...but you know it could be that you are actually kicking the crotch, er, clutch kill switch under the dash as opposed to something under the seat...if you have big feet that move around under there you could be killing a number of things...even the firewall pass-through wiring...

So many wires...so little time!

 

[Skyr]

Tore the seat and carpet outta it tonight and followed the wires from the harness back up wiggled giggled and even beat on all of them couldn't get the dang thing to cutout at all...LOL.. GOD I HATE WIRING!!!!!!!!..Im giving up till this weekend when I have time to actually dig in nonstop on it b4 I just lite it on fire and toast me some hotdogs over it... When I get it figured out ill make sure to post in on here and hopefully save someone else some time, and hair.

 

[saskbill]

Maybe time as you say, to step back and figger on this a bit. Maybe this doesnt involve wiring. Can you reproduce the problem by getting on the back bumper, or the hood, or the passenger seat? is there a possibility this about the truck shifting off level (or whatever its resting empty position? Not sure where I'm going with this if its all about whether you sit down in the driver seat or not, maybe nowhere.


Next time you have the seat out, maybe take a look under the carpet and see if there's any non-factory wires under there?