I have yet to have to go hunting a ground issue in my Sportage so telling you where exactly they are is best left for someone else (at least at the moment).

I can tell you, don't rely on a ground to be good just because it is tight and looks clean. Alluminum or copper connections on steel cause electrolosis and cause corrosion without any outside influences so even though the connection looks good, taking them off, visually checking and cleaning them and in particular cleaning any paint around the connection on the chassis, and reinstalling them is the only true way to know you have a good connection!

At my day job, we have a test light with 3 connections (one to battery, one to a good ground, and a probe we use to test each circuit in question,) that we use and it will sniff out a bad ground in a hurry. Red Light = "+12 volts or no ground", green light = "good ground or -12volts" and no-light = "no power or ground". If you want to go that fancy, you can buy one off the Mac tools truck for about $60.00.

If a circuit losses the ground or only has a partial connection, you will be able to read a voltage at that wire since the circuit will backfeed 12 volts to the point that the ground is lost. It is these "backfeed" situations where one circuit will start turning on another circuit on the same bad ground connection by creating a artificial ground for that circuit when it is activated, thus the activation of the rear defroster light when the brake lights are activated!

The lag in time for your rear defrosters to activate also constitutes a bad ground. When you turn them on, power is sent straight through the defrosters to the bad or partial ground. Heat is created from the resistance of the lost contact and when the circuit (or in this case connection) gets hot enough, the corrosion finally creates a temporary path and things start to work.

I wish I was close enough to help you out. I am still stuck to the ground theory though and a 3 connection test light is about the only way to truely do the test in a hurry and verify my beliefs. Otherwise, use a regular test light with the ground wire hooked to 12 volts and use the probe as a ground tester. If it lights when you touch a connection it's a good ground, be wary of anything that flickers or is dim when you probe it.

If all else fails, the first idea of removal and cleaning usually uncovers the culprit too.

I may now be in the same boat though as my dome light has quit working. Still has good bulb and good fuse, just no power to the light! hmmmm <img src="/forums/images/graemlins/confused.gif" alt="" />