I have a 99 F-250 V10 that has gone crazy overnight. I got in it and it was dead so I jumped it and let it run a little bit to charge back up when I shut it off the blower motor continued to run and the dome light flickered as well as a buzzing sound under the dash I charged the battery with a charger now the blower motor isn't running and the dome light has quit along with the buzzing, but now a box is clicking under the hood on the drivers side behind the headlight and now the transmission has started shifting hard and seems like it jumps into neutral. All of this seriously happened over night I'm so lost I have checked every relay on the truck and even replaced two that seemed bad, seems like there is low voltage or something that's causing these problems and causing the speed sensor not to work correctly but in not positive I have never owned a F250 and don't know much about them. What could be Causing this out of no where random issue?

 

How old is the battery? It may just be too worn out to hold a good enough charge to keep the electronics working right. I would go get it load tested.

 

It's a brand new battery, about an hour ago I went under the dash and grabbed my fuss block to take some bolts out and when I moved it everything went crazy so I have found my problem lies there I removed the wiring harness on the back of the DEM and both plugs from the side of the DEM removed the fuse block and DEM and I found that everything is full of mud and green acid looking substance. So I blew it all out with air in the morning I will spray it with contact electrical cleaner get them back to new where they can make great contact and hope all the mud is the problem, the previous owner apparently loves mud I have been cleaning mud off of it for two weeks. Thanks for your input I appreciate it.

 

Cleaning the connections may help your problem temporarily, but it probably won't fix it permanently. Here's why. All of the electrical contacts in your truck are all plated with various metals to improve conductivity / reduce resistance. This plating also prevents corrosion. Once corrosion starts, the first thing it takes out is the plating. Once that plating is gone, it's virtually impossible to prevent more corrosion from coming back. As you have already found out, corroded contacts make lousy electrical connections due to the increased resistance.

By using any of the various Electrical Contact Cleaners available at Parts Stores, you might temporarily get your conductivity and thus functionality back. But as I said above, the corrosion will come back pretty quickly and foil you again. I'd suggest applying some kind of corrosion inhibitor to the contacts after you clean them as a stopgap measure. The only real long term fix though is new parts - and that's going to be very expensive.