2004 Ford Excurison XLT 4X4 V-10 Gas 6

First of all check the smaller battery cables, particularly the positive one where it bolts to the under-hood fuse box. Be sure that is tight. Also check the negative one where it bolts to the body.

Running new new wires is not the way to fix a problem unless someone cut the insulation and the whole piece is corroded. I never allowed my students to do that. The proper thing to do is perform a series of voltage tests to identify the break, fix it, but most importantly identify WHY it broke. If a wire was rubbing on a sharp metal bracket or laying on a hot exhaust part, it is only a matter of time before the other wires in that harness will suffer the same fate and you will have to start troubleshooting all over again. When you finally get a professional involved he is going to disconnect some things so he can take measurements, and custom, add-on wires that he doesn't know about will seriously confuse the issue and cost you a lot more money for his time. I was involved with one in particular that would have taken less than an hour to find but the owner was not aware that someone previously had switched two wires in some misguided attempt to "fix" something. The result was well over 30 hours over nine visits before I figured it out. Once the cause was located, (only three feet away from where someone cobbled the wiring), it was easy to see why it had the symptoms it did, and luckily the owner was very patient, but all that aggravation could have been avoided it the first person had just diagnosed it properly and fixed it right.

You also have to understand that Ford's insane engineers have gone out-of-control with designing in inappropriate technology that adds unnecessary complexity to their vehicles. In this case the instrument cluster is the most intelligent, (complicated) computer module on the vehicle. They don't do anything that other vehicles do; they just add a computer to the circuit, and computers in that environment are very unreliable. Road and engine vibration degrade electrical connections. Body flexing over bumps in the road and when cornering put varying stresses on electrical connectors. You can expect to be chasing electrical problems forever. Mechanics and others who understand that throw up their hands and run out of Ford new-car show rooms where they promote all that technology as something to be desired. We all know the problems that are going to occur and the frustration and expense that will result.

There have also been a real lot of problems on Fords associated with the "GEM" modules. That is their "Generic Electronic Module" which is their name for the Body Computer. I've never been involved with one myself but I hear and read about them all the time. Most problems come from water leaking past the windshield and dripping onto the computer. It is involved with the things that never needed computers before like power windows and locks.

You also have to consider loose terminals on the connectors on the back of the instrument cluster. This is becoming more common on all vehicles now that they are all computer modules instead of simple gauges and lights. If it looks like the cluster is involved in the problem you will want to get the dealer's repair department involved. The anti-theft system is partly incorporated in the cluster. The cluster is even one of two computers involved in blowing the horn. It is the most common cause of a dead horn, and that repair generally runs around $800.00. THAT is what we mean by "inappropriate use of technology". My ten-dollar relay works my horn as well as Ford's two computers. A replacement cluster will likely need to be programmed to the truck, and if anything doesn't work once it's installed, it's their problem and they will have to sort it out. The days of adding custom wiring, even for simple things like trailer wiring, are long gone.