what are these wires??

[chevyguygoneford]

i just bought my first diesel and my first ford ever (as far as trucks go anyways) it is an 05 f350 exstended cab 6.0L 4x4 flatbed. under the hood on the fuse relay box there is velcro on the cover and there are 4 wires a black, blue, red, and yellow wire that apear to be factory coming out of the wiring harness rite beside the wires going to the hood light and apear to have gone to what ever was velcrowed to the fuse block cover. they are just cut about 3in long not caped or anything. the truck has trailer breaks but the controler plugs into a factory plug and it had a cb which is no longer there pretty sure these have nothing to do with it. it has piller gages but have traced them and no relevence. has factory radio. thats about it. also can i buy a replacement mirror marker light without replacing the whole mirror? any help is appreciated.

[Rattler-FX4]

Believe those are for the 4 up-fitter switches on the dash.

Not sure if you can buy just the lens for your mirror. Good luck with that.

[chevyguygoneford]

thanks for responding greg, what is the 4 up-fitter switches does it have to do with the 4wd??? i have tested them in many diffrent situations like in 4wd and lights on and radio on i tried it all and they never seem to have power to them.

[MPTonyT]

The upfitter wires are above the emergency brake if im not mistaken. Also not sure what those 4 are for. I know what your talking about though.

[mbahr22250]

If you look up under your dash on the drivers side, just above the kick panel next to te parking brake pedal, way up there next to the fire wall you will see the exact same wires bundled together (you may need a flashlight). They're there so you can wire up extra stuff without having to punch holes in your firewall. The wires are already run.

[GregsSD]

They are the factory "Pass-Through wires".
They are extra wires that go through the firewall so you don't have to run your own through. The other ends of the wires are under your dash, just behind the fusebox.

[coltsfanjmcguire]

Actually ford just ran those wires thru the firewall. They are open under the dash behind the fuse box also. They can be used with the Aux (upfitter) switches but they aren't connected to anything.

[symbols]

Yes you can buy just the lense for the mirror

[chevyguygoneford]

thanks everyone i appreciate the help now what is the standard procedure for letting your glow plugs heat up befor start up in winter and summer and would a block heater be a good idea since the pump has a built in heater? like i said before this is my first diesel. and do you know where i can get the mirror light and lense online i hate the parts department at my local dealership bad exsperence worth not going back over.

[amdriven2liv]

Originally Posted by chevyguygoneford

a block heater be a good idea since the pump has a built in heater?

You already have a block heater in your engine. The cord attaches just above the starter, and the factory (if it is there) ran the cord to the front bumper just inside the passenger side fog light. Reach above the starter for the cord. If it's not there, you can get one off ebay or from Ford or International. There are other places to buy them.

Links:

Diesel Technician Society

Do some research, some plug the extension cord into a timer to start the heater 3 hours before you get up.