Just bought a new starter for my 98 expedition hooked it up and the battery sparked so bad it almost melted the lead do I have the starter hooked up wrong or could I have a bad ground?

SOURCE: Negetive battery cable sparks when Itry to connect i put new altenator&starter selenoid

I had a similar issue and found that the connections at the starter shifted and created a short. An old friend of mine kept frying the starter solenoid wires and kept a spare set along. He beat the problem by replacing the main ground strap/cable from the battery to the chasis. Age caused too much ground resistance and caused the ignition wires to overheat and melt. Another friend was on his fourth alternater on a Landrover when I suggested he look at the battery ground.

SOURCE: 1995 lincoln continental wont start

have you checked out the core packs? and if you go to autozone you can get a printed diagram where the crankcase sensor is located also look for the location normally under the hood for the fuel pump relay

SOURCE: new starter and battery and still won't start

Could be voltage regulator or starter relay has also gone bad. Seems to be fairly common in the Bauer editions.

SOURCE: 2008 GM Melted ground wire/headlight plug - why ?

On your bulb. It should be labeled DOT 12V and then have something like 45W,50W, 55W or whatever wattage your bulb is. If it doesn't, then the bulb is not a proper bulb. I've seen a lot of people installing aftermarket bulbs that burn the wiring and harness because the bulbs draw much more power than the wires are designed (I've seen some install 100W bulbs for 50W harnesses)

If the car was purchased new and the bulbs are the original bulbs, then I don't believe they would. In that case, I would be lead to believe it is an issue with the harness, which could cost upwards of $100. You could splice in a new wire (14GA and better recommended). I don't think headlights are covered under warranty, but you could give it a shot and see what they say.

SOURCE: 1998 Pontiac transport van wont start:

Well you hit all the major ones, could be crank position sensor, ignition module, a bad coil pack (it should have 3), you need to check that you have spark to each plug while the engine is turning over (!!!be careful as this will hurt if you get shocked!!!), this will rule out coil packs. if you have no spark to any plug your looking at a bad ingnition module (which is what the coil packs bolt to). Hope this gets you on the right track!