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Daniel Wilson
Daniel Wilson,
Category: Medium and Heavy Trucks
Satisfied Customers: 5409
Experience:  Owner at DJ Wilson
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Where is the relay shut off solenoid located on an 1998 ford

Customer Question

Where is the relay for the shut off solenoid located on an 1998 ford f-800 with 5.9 cummins. My truck starts and dies as soon as key is in run position. I changed solenoid and still does same thing. I'm told thur relay is bad I can't find it
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  Wayne replied 1 year ago.


I'm Wayne I will help you with this

most time it is not the relay, but the oil pressure switch

you you turn key to start it puts power to the solenoid

and when you let key go , power drops out

then the power from the oil pressure switch holds it in

unless you loose oil pressure, then it drops the voltage to kill the engine

I suggest you replace the oil P/Switch

I hope this helped you

Hi if this helped you

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Expert:  Wayne replied 1 year ago.


I am just following up with you

did my answer help you

let me know, Please


Customer: replied 1 year ago.
Thanks Wayne. I just ordered the oil pressure with from local dealer. It will be a couple days My oil gauge on dash is working. But I think there is a seperator switch for it. I will respond as soon as part arrives
Expert:  Wayne replied 1 year ago.

Ok, Let me know

Customer: replied 1 year ago.
Hello Wayne. I finally got a chance to put oil pressure switch on truck. It didn't help. Truck will start right up fine. When u let off the key switch the engine dies. I put the old kill switch solenoid back on. And same thing. Any other suggestions
Expert:  Wayne replied 1 year ago.


Sorry for the delay ,I was out all morning

have someone crank the engine, and with a test light

check for power on the F/solenoid, should have it on 2 of the 3 wires

let me know , please

Customer: replied 1 year ago.
I unplugged the wire from f/solenoid. Only the middle wire had power when cranking engine. No power at all when key in run position
Expert:  Wayne replied 1 year ago.

Thank you for that

you need to check it when plugged in to Solenoid

Customer: replied 1 year ago.
Just tested wires with them plugged up. Engine cranking. Only middle wire has power everything is same as when I had it unplugged.
Expert:  Wayne replied 1 year ago.


Thank you for that

now go to the ign switch, test the power

at the switch, you should have 2 wires hot when key goes from start to run

Customer: replied 1 year ago.
Ok Wayne. There are 10 wires in the harness going into the steering column. 6 of those have power with the key on.
Expert:  Wayne replied 1 year ago.


I am going to opt out of this and send to another expert,

I don't have wire diagram for Fords

Sorry I could not help


Expert:  Daniel Wilson replied 1 year ago.

Hi my name is***** will be glad to help. The relay should be on the drivers side fender well. let me pull up a diagram of that circuit

Customer: replied 1 year ago.
Hello Daniel On this truck the hood flips forward. It has no fender wells
Expert:  Daniel Wilson replied 1 year ago.

There are 3 wires going to the FSS, Ground, Hold and Pull.

"Ground" wire, truck side is black with a orange stripe, FSS side is all black, it is connected to ground all the time.

"Hold" wire, truck side is small light green with a black stripe, FSS side is normal sized Red wire, the Hold coil (an electromagnet) gets power when the key is in the run position. Since the plunger is spring loaded to push the lever down (turn off engine). The Hold coil Does not have enough power to pull the plunger up (compress the spring), and only has enough power to keep the plunger up, once it's all the way up (keep spring compressed). So in order for the hold wire to hold the lever up, the Pull coil must bring the plunger all the way up first.

"Pull" wire, truck side is Red, FSS side is White, the Pull coil (an electromagnet) gets power only when the starter is engaged. it has plenty of power to pull up the lever (compress the spring), but if it's kept on to long it will create a lot of heat and will burn up the FSS. the Power wire gets power from the FSS relay(Part# *****), the relay gets its signal power from the small wire coming off the starter.

Expert:  Daniel Wilson replied 1 year ago.

here is the diagram for the fuel shutoff circuit

Expert:  Daniel Wilson replied 1 year ago.

Sorry about that. It should be mounted on the firewall.

Expert:  Daniel Wilson replied 1 year ago.

Check the wiring from the starter and for an inline fuse in the harness as well