1999 jeep grand cherokee code P0108 - 2001 Jeep Grand Cherokee

SOURCE: engine code 95 jeep grand cherokee lerado

12 is a battery disconnect within the last 50 start cycles and 55 means the end of the diagnostic cycle.  Basically the computer found nothing wrong. The 12 code may seem incorrect if you haven't disconnected the battery recently, but from my experience the 12 code shows up almost all the time regardless.

SOURCE: 1999 jeep grand cherokee all time four wheel drive will not engage

Sounds like the splines on your transfer case gear are ground down

SOURCE: Jeep Grand Cherokee Limited P0700 diagnostic problem

P0700 means there is a transmission fault code in the transmission controller. Since the transmission controller doesn't have a light attached, it tells the engine controller to turn the light on using this code. You'll have to access the transmission controller to further diagnose the problem.

SOURCE: I have an engine code for a jeep grand cherokee

ignition/distributor engine speed input circuit malfunction

SOURCE: shift indicator light 1999 Jeep Grand Cherokee

There are two parts to it, a voltage resistor, and the EL panel itself.

You need to remove the console first. There are 2 screws under the front rubber pad, two under the cup holder, two in the bin. Remove those six first, take the storage bin out, then slide the rear cupholder out, remove the two screws under the cup holder, and one in front of it.

There are a total of 6 flat screws, and 3 self tapping screws you have removed.

Put the parking brake on, shift the tranny to N, and the transfer case to the middle position if equipped.

Remove the entire console. Slide the shifter beezel as far up vertically as you can. There are 4 clips you ned to remove to do it.
You will see a blue and black wire running into the back. Follow those wires to the resistor. You will see a transparent EL panel attatched to the resistor by two clips.

Usually, one or both of these clips has come loose, causing the light to work intermittantly. Clip them back on, and turn on the headlights to confirm that the light works correctly now.

Re-install everything in the opposite order.