My 1999 (57K miles) Isuzu Rodeo 4WD light is blinking and would not go
away. It is actually stuck in 4WD so I took it to Dublin
Chevrolet/Izusu for repairs. They first said that front axle 4X4 module
is faulty and needs replaced. After replacing still the same. Then they
said that brain (?) behind 4X4 is bad so it was changed, same results.

Now, it is Friday and my vehicle has been with them since Wednesday; I
am worried that they may keep replacing (at my $$$ expense, offcourse)
parts one at a time until it is fixed. I would rather get an upfront
estimate and then decide what I want to do. Are they correct in their
approach?

Any suggestions on the problem or their approach of fixing this
vehicle? Much appreciated.