[/IMG]What is this wire and do I need it connected?
Also do you think my battery wire on the right is too corroded?
The truck is an 89 f250 with a 7.3 idi. I'm gonna try and post a pic but can't figure it out

http://i91.photobucket.com/albums/k3...psnriuhaeo.jpg[IMG]

 

[QUOTE=78Fordbc;14231424]What is this wire and do I need it connected?
Also do you think my battery wire on the right is too corroded?
The truck is an 89 f250 with a 7.3 idi. I'm gonna try and post a pic but can't figure it out[/.

It's the little wire that connects to the positive battery terminal on the driver side battery.
It's coming from inside the dash. It might be the wire to the glow plug button maybe?
Can anybody help? I can't get a picture to work.

 

Whatever that wire is, it sure ain't factory.

And yes, your battery wire is looking a bit worse for wear. More concerning is the lack of real sheathing. Is that whole cable just a bare wire covered in that cheap sheathing stuff? If you're having slow crank issues, that might be a place to start.

Mike

 

My 85 has a yellow wire like that coming through the firewall too, came like that from the factory. I assume it is for an accessory or optional equipment that my truck doesn't have. I'm now using it to power my electric fuel pump through a fuse and relay. Someone used yours for the inline fuse. Check it with a test light or volt meter to see if it has power. If so, you should tape up the end to prevent shorting.

 

It still starts without the wire connected but ya I have no idea what it is.
I was having slow crank issues but I just recently replaced the cheap Bosch glow plugs that the PO had put in and it fired right up. All except one glow plug was swapped for motorcraft plugs because one had the head rounded off and I can't get it out!
And yes that battery cable is just electrical tape and cheap sheathing. I think I'm going to replace both negative battery cables as the other one isn't looking much better.

 

Just went to start my truck and the starter got stuck on?!! Popped the hood and ran to get something to take off a battery terminal and the passenger side battery cable melted right off at the battery post. What could cause this to happen? I just replaced the starter a couple days ago now I hope I don't need a new starter already!
I looked around and I could see a little bit of bare wire on the neg battery cable where it connects to the block. Could that have caused this?

 

Check the starter solenoid on the passenger fender, it may have stuck on.
The cable probably melted from excess heat caused by running the starter for too long, combined with the increased resistance from the old nasty corroded battery cables you have.

First thing you need to do is replace the battery cables, both positive and grounds. Check the fender solenoid and the solenoid on the new starter.
Looks like at least that one battery is 5 years old and possibly near the end of its life. Why did you replace the starter?

 

Yes tomorrow morning I'm going to go buy some new battery cables at napa. I already have them removed. The negative cable on the drivers side had its casing pretty much completely falling apart in little pieces. The rest was all electrical tape and some cheap sheathing.
On the positive cables I think I might just be able to put on a new terminal to the drivers battery side of the cable and it should be alright.
I'm also going to pick up a new starter solenoid so I can switch it up if that turns out to be the problem. If not I'll have a spare. I know the batteries are probably pretty old but I just bought this truck from some guy looking to get rid of it for 1000$ So I'm still trying to fix up all the neccesary things to make this a reliable truck. This is also my first diesel and I'm still learning everything.
I had to replace the starter because when I had the old plugs in I had to crank it a bunch to get it to start. Most of the time I even needed a boost. Ended up burning out the starter from cranking to long and not giving it sufficient time to cool. Rookie mistake!
Do diesels need special batteries or will any truck battery work?
Also how do I check the solenoids?

 

Found this is where the yellow wire tucked by the drivers side battery goes to. It's mounted on the fender on top of a starter solenoid. Do these trucks have starter solenoids on both sides? The black wire connected to the positive bat cable goes into the cab on is hooked up to a switch on the dash. I think it might be for those backup lights on the rear bumper. Does anybody know what the thing in the picture is? It's hooked up to that solenoid on the drivers side.

 

Also I have this mystery wire that's yellow and blue. Anybody know what or where it goes? And then there is two exposed wires that I'm not to sure about??

 

the yellow and blue looks like the water temp its on the flat sloped part of the block in front of the head. and the exposed are the tach sensor, only available from ford about 60 bucks

 

the diesel engine requires a lot of current, that's why two batts, to start so they have a starter relay on the fender that must be used, so as not to stick on, and it must be wired correctly, or it will not provide protection, the starter has its own solenoid also.

 

I know all about the starter solenoid on the passenger side fender from my 78 f150. Had that problem a couple times already. I also recently noticed one on the starter when I installed it. But what about the one on the drivers side fender?

 

the wire in the first post picture is part of an aftermarket fuse holder.

the second picture in post #9 is a 35 amp circuit breaker
the solenoid on the driver side fender was probably for a snow plow.

someone was not very nice to the electrical system in that rig.

 

solenoid also may be for charging a camper battery.
I second that on the botched electrical system.
that looks like a car battery and they wont cut it, you need diesel grade batteries for it, get 2 new ones before low voltage burns up the new starter.