1998 Trooper. Has Traction on Demand 4x4.Check light blinks in the TOD gauge when in 4 wheel drive. Apparently I don't have drive to front wheels in high range but low range shows it has locked 4 wheel drive. What is going on? And can I drive it in low range? Thanks

Most likely one or both of the vacuum switches that control Lock/Unlock of the front axle is bad. Same thing happened to me about a year ago (only the Lock one was bad, had a leak).
The service manual has a step-by-step to trouble shoot it.


BTW it's only sold as an assy.
St Charles Isuzu has the best price and free shipping.