This is going to get long...my 2001 F250, 5.4L 309,000 miles: Intermittently over the past few months, the blower fan wouldn't turn off with the ignition off, key out. So, I made it a point to turn the switch to "off" when I was done for the day. Forgot over Thanksgiving, came home to a dead battery, charged it several hours, seemed ok. Started it up, drove 8 miles, came home, shut it off. Two hours later, no crank. Put the charger on, still no crank with the key. I turned the key to the run position, put the + lead of the charger to the starter solenoid, it cranked over and started fine.

After that, the power windows and map lights would only work when the gear selector was in reverse or drive, 2, and, 1. The radio is on ALL the time but would only have sound when the gear selector was in Park or neutral. The headlights/taillights were on all the time, when switching from low beam to high, the speedometer needle would spike down 10 mph (vehicle speed unchanged, just the needle twitch) and back up, going from high beam to low, there was no issue.

Last night I disconnected the battery so it didn't drain overnight. This morning, re-connected it still no key crank, so jumped power to the solenoid to start it. The windows worked initially, now they don't, radio has sound in all selected gears but still wont turn off, map lights inop, head/taillights work as they should.

I've glanced at the wiring some, nothing jumps out at me. I did disconnect the electrical part of the ignition switch and the radio still stayed on. I don't have much time to fool with it and I don't wan't to spend big bucks at a shop. The truck has minimal cash value but does have high "user" value for me.

Does anybody have any suggestions where to even start?

 

 

 

In looking under the dash for water infiltration I didn't see anything. I opened the hood to check the cowl area, saw the copper braided ground strap to the firewall on the passenger side, gave it a light tug and pulled it out, it's still attached to the firewall but not the other end, I'll figure out where the other end goes and run a new wire...we'll see what happens.

 

Any idea where the broken end should attach?

 

 

Thanks for the input but I dont think so, i pulled it up and out from along the firewall, it seemed pretty well rooted down towards the rear of the block. I also have an '01 F350 with a 7.3. I'll look at that for comparison when i get home. I did find another broken ground strap on the passenger side between the frame and cab. I picked up some 8g wire and ends. Until i have the obvious broken ground straps repaired I'm not going to think too much more into it. I'll let you know my findings.
i really do appreciate your response, and the responses of the others. I needed some encouragement today and I thank you all for it!

 

 

I have a 2003 F250 5.4 and my ground strap also corroded. The other end bolts to the Trans dipstick tube mount tab. Check under you cab on passenger side by pass. door, you have another ground strap that goes from body to frame. Mine was almost totalty gone. I did not read your whole post, I see you found the other ground strap under body on pass.side.