I found a random ground wire, seems to be coming from the back of the valve cover on the passenger side. I cant get to or see where it goes but i hooked it to the firewall, anyone have ideas

 

Picture?

 

I would if my camera worked, its a flat braided wire with a jagged mounting thing at the end

 

You found the engine/firewall ground. It's a common one to be found dangling. It's a small copper braided ground (as you posted). One side to the FW, other side depends on the manifold.....whether it's plastic or metal. If your intake manifold is metal, connect it anywhere convenient. ...there's quite a few empty thread chambers to mount to on the metal intakes..doesn't matter where. If you have the plastic intake, Ford uses a location on the front of the engine instead. The ground runs between the manifold and cam cover routing to a location in front of the engine.

 

Now im new to all this, i hooked it up and everything, but what is its function, does ot make anything run better, enable something to work orrrr....

 

Electrical components require 2 things, power and ground. You found a ground wire dangling. By reconnecting it you simply completed the circuit for something built into your truck.
.

 

It's a isolated ground, no power. Grounds the engine to the cab and vice versa. There's another under the cab, grounds the cab to the frame....if it hasn't rotted away.

 

These types of grounds are used to minimize RFI (Radio Frequency Interference)

 

My kids first car was an 87 pathfinder. The rubber band timing belt broke and it wiped out all the valves. So we rebuilt the top half of the motor and put it back together and it wouldnt start. Ended up it was a ground wire like that one. When I found that wire and grounded it started right up. Guess We have a secondary ground..

 

Yes, but that's just a small part of what they do. Straps are ground redundancies. They do a everything from saving your heater core/cooling system from electrolysis to maintaining all circuits in the dash, engine and PCM..even the GEM. Ignoring them when broken because you don't understand is kind of crazy. Your asking for gremlins in these systems. When the shortest path to ground isn't available, there's another path to take. Although the strap from cab to engine isn't a high power ground like starter and battery, it maintains many circuits and prevents internal corrosion. Which in time causes head gasket and cooling system failure.

The most I noticed right off after going through the grounds (I know where they all are on this truck lol) is that everything worked. All the lights in the dash worked again, no strange problems, the windows and door locks worked like new again, fast and responsive. These were just the things I noticed. But the 98, which has surpassed the 350,000 mile mark has never had a heater failure or cooling system problem. This is a payoff of good maintenance yes, BUT, - a big part of that was servicing the grounds. These trucks suffer a bit do to electrolysis issues. How much they do varies. This may go unnoticed for long periods in time. During so, it's feasting, corroding up engine block cooling pathways and cooling system internals. This, -more times than not, leads to your engines inevitable compromise. A simple/not so simple (depends how you look at it lol) grounding issue could and has been the root cause. Immediate concerns, we HAVE TO deal with, but it's those slow death and preventive things that get over looked. Grounding, - it's on the list, towards the top on some of them I expect.

Anyway, for 123, - even if you don't understand what it's for, fix this one. It may just fix a lot of other issues you or anyone else don't understand (worked for me)...it could also cut way back on your new thread tally lol. Which is great all around for anyone...problems suck, the less the better. There's your simplified explanation, hope it helps.