auto mech. needed. im clueless!

[ps2/bikevision]

when it comes to cars and trucks i think i have a fair knowledge. but ive been stumped.

my dad has a 99 f350 super duty diesel. the other day he got in it and it wouldnt start. so we check the batteries and one is low. so i pull the battery out of my truck and throw it in his. still wont start. so i grab a screw driver and jump the solenoid and it fires up. so off to the parts store he goes and comes back with a new solenoid and 2 new batteries. (his where do to be replaced) after installing the new batteries and solenoid it still wont start. i check the fuses and one is blown, so i replace it. i turn the key to the "run" postion and it fires up and the starter wont disengage. so i go out pull the wire off the solenoid and the starter shuts off. i grab my 12v tester and find that when the ignition is at "run" there is power going to the solenoid, when you turn the igniton to "start" there is no power to the solenoid. the first thing i think is the iginiton switch is bad so i get a new one. (it was cheap) this still didnt solve my problem. also the back up lights quite working too. early that day before all this happened we could smell what smelled like a burnt wire in the truck but couldnt figure out where it came from. the only thing i can think of is the neutral safty switch is bad but i dont have a way to test it and the cost of just buying a new one if thats not the problem is to high.

anyone have any problems like this before. 

[haunter]

definitely check the wiring to the lights and etc, sounds like something fried and is really fucking up everything

[Lucky]

you have the 2 wires to the solinoid reversed..

[ps2/bikevision]

i found 3 wires that were bare but not touching and fixed them. didnt fix the problem. 

there is only three wires to the solenoid. two big ones that go from the battery to the starter and a little one that comes from the iginion to the solenoid. this wire goes on the S terminal.  the other terminal I goes to the distributer on older fords and is not used on new ones. the problem is the wire from the igintion is hot when the key is on. and not when its on start. its like its backwards from what it should be. 

its raining now so when it stops im gonna check the wires really good again.

[Walt_M.]

That hot wire when the key is on is probably for the glowplugs, you did say it is a diesel? So you just need to find the wire from the switch to the solenoid.