I have a 1998 chevy k2500 pickup with a 5.7L V8. The problem i am having is with the 4wd. it has a 3 button electronic shift selector. when pressing the 4wd low button it will shift the motor and the front diff actuator into 4 low. if u put it into 2wd it will disengage but the light for 2wd does not come on. if u put it in 4 high it will not shift at all but the lights for 4 low and 4 high illluminate. if u keep doing it for a little bit shifting through all of them fuse #2 in the ip fuse block blows. it has a new selector switch, a new encoder with motor, and a new transfer case control module. I am truly at a loss. hope u can help.

USA truck or export? to where? Gen 3 or 4.
2wd./4wd, got 2 fuel tanks or 1.
NO engine told and fuel systems vary by, DING engines there.
Gas or Diesel>? 5.7 L Oldsmobile diesel V8

TBI , is this Throttle body with injector 1 engine.
there are 3 answers.
the fuse box is marked
the lost glove box guide book shows fuse
the service manual online show all this.
or google it.?
ECM_B on some, label on fuse marked, clearly

the list of engine this year is huge. NOT Z71 right>?

250 cu in (4.1 L) I6 (Argentinian-made versions only)
292 cu in (4.8 L) I6 (Mexico only)
262 cu in (4.3 L) V6
305 cu in (5.0 L) V8
350 cu in (5.7 L) V8
454 cu in (7.4 L) V8
4.2 L MWM Sprint 6.07T I6 diesel (Argentina and Brazil)
379 cu in (6.2 L) diesel V8
395 cu in 6.5 L turbo diesel V8


3 - ECM B 10 Amp (Red) (Gasoline Models) Electronic Control Module Memory, TBI Fuel Pump, TBI Auxiliary Tank Selector Switch

wild guess engine

The selector drive mtor mounted on the transfer case had alot of problems with water getting into the circuit board and also the mtoro drive getting stuck. At the dealership I have replaced hundreds of these over the years.

The 4wd shift knob should be on the floorboard, the actuator that sends the power to the front axle would be an internal part of the transfer case

Well it could be the selector switch, but I doubt it.
Generally, the service light means something is not working that the computer controls. Solenoids and valves are a couple of possibilities.
The transfer case is shifted by solenoids commanded by the body computer based on the switch position on the dash.
You should be able to have a shop scan the body computer for trouble codes and proceed from there.
A basic code reader may not access the body computer.

As I recall the 96 blazer had electronic shifting for 2wd to 4wd. There should be a small panel on the drivers dash buttons for 2wd, 4wd lo and 4wd hi.

Simply press the desired button while stationary and if the system is functioning properly then it will shift and the light for the engaged type of drive will be lighted. Generally you would like to be in 2wd for this vehicle.

your transmission has possibly been rebuilt with stronger springs put in. No worries. have been running mine for along while without any problems. Better this than slipping, but it is a bit annoying.

by swapping vaccum hoses on front diff shift on fly unit you can get out of 4wd or vise versa or by removing and sliding sleeve ring inside diff tube over, check range selection detent switch on this unit it is a on/off switch.these fail often

Under the battery there is a electronic vacuum valve that engages the 4wd,thes often go out,and your shift buttons will still show that 4wd is engaged,but isn't.I have had several s series blazers,and this component has failed on most of the trucks.

i have 2006 f250 4x4 will not engage unless i lock in hubs. once hubs locked in i can engage 4x4 by using electronic selector. why will it not engage when hubs are in auto and electronic selector is on 4high

1- STOP THE VEHICLE
2- MAKE SURE IS IN NEUTRAL POSITION
3- ACTIVATE 4WD (HIGH) MODE( MANUAL OR ELECTRONIC SWITCH SELECTOR
4- MOVE LEVER SHIFT TO ''D' DRIVE POSITION
IF THIS DOES NOT RESOLVE CHECK TRANSFER CASE SWITCH