Ford Repair: check engine light, spare fuse, blown fuses

Question
You are very hard to get to. You are always maxed out with questions. So, I will try to get you all the info I can, because I may never get to you again. I have a 1995 Explorer XLT with a build date of 4/95 and 160,000 miles. I think it has the 945 package on it. (Power seats, tall console, overhead outside temp and direction, and other stuff). The check engine light stays on all the time and I have not been able to get the Texas state inspection, so, it has been sitting in the garage for nearly 18 months. All electronics seemed to be working correctly when I parked it. It was missing real bad and the trans has a slight slip to it when you have your foot in it. I took it to the local auto parts the other day and they put it on a little handheld device to find out what the problem was and said it was the fuse that controls the computer. They pulled it out of the inside fuse panel and it was nearly melted on one side and the prong was very discolored almost blue, and then they put in a spare fuse. Shortly after starting the truck the light came on again. I know a little about higher voltage (120/240) and when you find a connection that has melted one side like that, that of course means that it has built up a lot of heat. This is usually caused by a loose connection. Can that be the case in a fuse box too? When you have the discoloration in higher voltage, it usually affects the other side of the connection too. If that is the case, how would you repair the contact point in the fuse box (where the fuse clamps into)to keep this from happening again? What caused it to happen in the first place? I don't know which fuse he replaced but I think it was a red 10 amp from the number 3 spot. I could be wrong. I don't seem to have anything that is not working now except the overhead console and I don't see any blown fuses. Their little hand held devise would not locate any problems and he blamed it on the fuse.
Can you tell me where else to look or what else to look for. I may not have a company truck to drive much longer and will have to have my Explorer back soon. Can you please help?
Thank you,
Sonny

Answer
Sonny, your question is very good and not something that I've seen very often!
Electrical resistance on the fuse contacts will make the fuse overheat and turn blue sometimes.  I've seen this before, and it was always after someone damaged the terminals of the fuse panel "piggybacking" an extra wire to the fuse for a radio, radar detector, etc.  The prongs of the fuse panel are then deformed, and fit loosely on the fuse from then on... creating high resistance, thus heat, weakening the terminal even more, more resistance, more heat, etc.
The fuse panel only comes with a complete wiring harness from the factory on most vehicles.  You can repair the circuit by pulling the two wires from the fuse panel and soldering in an 'in-line' fuse holder a few inches away from the panel.
Without knowing the actual circuit that the fuse controls, and the trouble code your PCM stored, I don't know if this is the cause of the check engine light.  It is possible - if that fuse powers the O2 sensor heaters, for example, then they would be inoperative with a loss of voltage and would cause the O2 sensors to fail a self-test after driving a couple of drive-cycles.
As for diagnosing your concerns;  you will want to fix the poor connection at the fuse panel.  Then, you need a schematic of the vehicle (maybe just the description of what each fuse controls, located in the owner's manual) to determine if any of the loads of that fuse are damaged and causing the high amperage draw.  Your local Ford dealer might print you out a few pages from their sources for the affected circuits in question.  
The engine miss and the check engine light could be related to a different problem, too.  You may need a trained technician to diag the cause, and then decide if the repairs are something you can handle.  The transmission slip could be due to low fluid level or plugged filter, so I'd check the fluid first and get the engine running right before looking to a transmission specialist for help.
Hope this helps...
Clay