It could be a problem with your neutral switch. When My switch went bad, I jumpered it so that I could start it while in gear. However, by jumpering the switch it didn't allow for the front wheel drive to turn on.
Help please dealer said switch good this is unit cant get in 4 wheel drive dealer said is brain and cost a load he shorted it out and now goes in 4 wheel but engine light stays on antone know where i could get brain to be able to use switch in 4 wheel 2 wheel and 1 wheel as it is suppose to work if not where i could take the unit to get new brain..... Im in gaithersburg maryland
Now have learned only goes in four wheel drive when back wheels are spinning so if need power back wheels need to spin assist 4 wheel what it really is so bipassed the brain and shorted it out so now can hit switch and really gets 4 wheel drive the only bad thing is engine light stays on