Condition: The green 4WD light is on when in 4H or 4L but there is no power to the front wheels. How come?
Problem: The front hubs are either damaged or not functioning.
Reason 1: If you have a 1995 - 1997 Sportage they came from the factory with Warn low speed automechanical hubs. These hubs wear out over time or may have been damaged due to a high speed shift from 2H to 4H. They were designed to be engaged either from a stop or under 15 MPH. Higher speed engagement will damage them. They also do not hold up well in rough off road conditions and will start disengaging even in 4WD.
Reason 2: If you have a 1998 - 2002 Sportage they came from the factory with "shift on fly" high speed vacuum hubs. With these hubs you could shift from 2H to 4H up to speeds of 50 MPH. It was a great idea but they don't work. The vacuum seals on the back of the hub area is VERY prone to leaking. When there is a vacuum leak the hubs will not engage. Kia attempted to fix this with a "double seal" design on later Sportages. That fix has been inadequate too. Once the vacuum seal is compromised dirt and moisture can enter the hub area and damage the wheel bearings.
Solution: There are 2 versions of hubs available from Warn industries that can be installed on any year Sportage. You can find Warn at http://www.warn.com
Manual Locking Hubs: Warn part number 60247. These are manually locking hubs that you must engage by hand at each wheel whenever you want to use 4WD. Once you shift back to 2H you can unlock them. You CAN leave them locked in while in 2H but fuel mileage will suffer because you are now turning the front axles and front differential. If the hubs are locked in you can "shift on the fly" at high speed. The advantage of these hubs is that they are absolutely bullet proof and reliable. They can take rough off road abuse and you'll always be assured that the 4 wheel drive will work.
Automechanical Locking Hubs: Warn part number 61918. These are a much improved version of the automechancial hubs originally installed on 1995 - 1997 Sportages. They can be engaged at much higher speeds and don't require vacuum for engagement. Disadvantages is that they are more expensive than manual hubs and they cannot take much abuse. They are for light 4 wheel drive duty only.
Installation: Either hub type can be installed on any year Sportage. Warn includes detailed installation instructions including pictures. Simply follow the directions for the ORIGINAL hub type you are removing. No special tools are required however snap ring pliers are helpful. On 1998 - 2002 Sportages there are some additional steps to take after installing the hubs. Remove the vacuum line in each fenderwell. Cut it off at both ends at the strut bracket. Plug the vacuum port on the backside of the hub with a screw and automotive epoxy. The vacuum line that projects into the fender area can be left unplugged. In the engine compartment locate the vacuum solenoid up behind the air filter. Unplug the electrical connector that comes up from underneath and tape it off. The plastic hubcaps on 1998 - 2002 Sportages will not fit over either hub. And you need access to the manual hubs to engage or disengage them. A solution is to slice off the top of the hub cap and then install it. Or leave it off. 1995 - 1997 Sportages have a different style hubcap with a plastic center piece that removes to allow access to the manual hubs.