My F-250's relay and starter burned out twice. I figured it has to be an electrical problem because the relay doesnt know to send power to the starter unless the key turns and sends the signal or is there another step that im leving out. I cant trust my mechanic to fix it because he said he couldn't find anything wrong. There is also a fuse on my relay from my stereo, could that be the problem and if so where else could I put the fuse and is there a cut off switch for the battery that I could put on without opening the hood and disconecting it by hand the way i've seen a few? I bought the truck off a friend and want to fix it myself as a hobby(and save money) unfortunately it hasn't been at my liesure. Its a F-250 Super Duty 2000. Any kind off help would be great because Im new at this. Thank You

 

Shorts in wiring harnesses are not fun to find.

It has been a while since I had a 2000 Super Duty, so I will throw out some general ideas.

The stereo wire should not have anything to do with acuating the starter relay, unless it is somehow touching the actuator terminal. Disconnect it and see if the relay works correctly or not.

Check all of the battery and starter cables for shorts to ground.

Disconnect the wire that atuates the relay and check if there is any voltage present.

I cannot remember if the 5.4 has a typical Ford starter solenoid on the fender or not, but there were some bad ones in the parts stores about two years ago, I put three on my daughters 85 F-150 before I got a good one. It really isn't fun trying to disconnect a battery cable at a gas pump with no tools.

Robert

 

Thank you for the information I greatly appreciate it. This is one frustrating hobby especially for not having much knowledge in this area.

 

Do you know if this vehicle has any kind of auto start system presently on it?
Also can I ask where the replacement starters were purchased?
Since you stated ,your mechanic, is it safe to assume you didn't replace the starters yourself?

 

I replaced the starter myself. The starter came from a place thats been in business since before I was born called Rayelco Generator Co., Inc. in Lodi New Jersey. The relay I bought at a auto Parts Store called Carquest Auto Parts in Pequannock New Jersey. The mechanic put the second relay on and I dont know where he got it from and the second starter he put on but I took it back to Rayelco's and they fixed it. There is no auto starter or keyless entry system on the truck. There is a in-line fuse on the relay for my amplifier for my stereo and there was a fuse in it when I brought to the mechanic and now there is not. When I put the new starter in I turned the key and nothing happened, just a click, then I took the key out and took one step from the truck and it tried starting itself. Then I changed the relay and it started and my overdrive was flashing on and off, I got the truck home and the next morning it wouldnt start and had to call my mechanic to come and get it. And he said it was a bad relay, that was new not even on the truck 12 hours. It has been working since but Im worried that the problem is still there somewhere in the electrical wiring or can it be the ignition switch, where you put the key in and turn I think thats what its called, is bad? I figured that it would be the ignition switch be cause that tells the relay to send juice to the starter to work or am I leaving something out besides that the amplifier is connected to the relay(I didnt have the speaker system installed my friend did who I bought the truck from).

 

Most of the time places that do starter and alternator rebuilding are better than run of the mill aftermarket starters etc. Sometimes when people connect add on equipment like stereos etc., they don't always use the best place to tap into for power and ground.
It is possible that one of the starter relays was defective, but if there is some additional wire connected to the wire going to the solenoid that energizes it only at certain times it will take some serious checking to verify it. Nothing should be tied into that wire whose power originates at the start position of the ign switch and goes through the range selector switch (neutral safety) to the primary solenoid on the fenderwell or firewall which then energizes the solenoid on the starter.
Until you can find that intermittent problem that energizes the starter, your vehicle is not safe to work on without disconnecting one of the battery cables first. Sometimes wires are tightened and move to where they make contact to a hot source. That needs to be carefully checked out.
The ignition switch assy is located on the steering column behind and below the dash. If possible disconnect the wires (hot supply and ground both) going to the add on stereo for a while and see if the problem still is present.