I have a 04 chevy avalanche z71. My four wheel crive system wants to try and change from 2wheel to 4 whheel high or low while driveing. Sometimes at start up the red light under the 2 wheel high button comes on the problem is intermitent . Also occasionally the service 4 wheel system light comes on, however it was serviced this year.

SOURCE: 1994 chevy s10 blazer 4x4 push button type

small sylinoid on the top of the transfer case needs replaced. easy to do. it has three vacumelines going to it just trun out and replace like a bolt.

Joe Lamb

• 463 Answers
• Posted on Mar 27, 2009

SOURCE: 2000 silverado z71 service 4 wheel drive light on/off

The problem is with the front actuator.Its flashing in the dash lights because is not functioning properly.Replace actuator and fix problem.Its a 4 or 3 wire screw in plug in front axle,,

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SOURCE: Were is the fuel Filter

LOCATION OF FILTER IS DRIVER SIDE FRAME RAIL ABOUT AT DRIVER DOOR HARD TO SEE BUT FALLOW FUEL LINE ITS THERE. hOPE THIS HELPS PLEASE RATE ME !! THANK YOU AND GOOD LUCK

TOOLS Are Simple and inexpensive local Parts Store like AutoZone will Have it

FUEL FILTER REPLACEMENT

TOOLS REQUIRED
J-46363 Fuel Line Release Tool

REMOVAL PROCEDURE

1. Relieve the fuel system pressure. Refer to Fuel Pressure Relief Procedure.
2. Raise and suitably support the vehicle. Refer to Vehicle Lifting.
3. Remove the fuel composition sensor bracket nuts.Reposition the fuel composition sensor/bracket off to the side
   1. Using a flare nut wrench and backup wrench disconnect the fuel line fitting from the fuel filter.
   2. Pull the quick connect fitting back until the internal retainers hit the filter stop.
   3. Twist one end of J-46363 and insert it between the fitting and the filter.
   4. Twist the opposite end of J-46363 and insert it between the fitting and filter.
   5. Once J-46363 is inserted, ensure that J-46363 is parallel to the filter and fitting.
      1. While holding the filter, push the fitting towards the filter in order to disconnect the quick connect fitting.
      2. Remove the fitting from the filter.
      3. Remove J-46363 from the filter.
         1. Remove the fuel filter from the bracket.
         INSTALLATION PROCEDURE
         
      4. Install the NEW fuel filter to the bracket.While holding the filter, push the fitting towards the filter in order to connect the quick connect fitting
      5. Using a flare nut wrench and backup wrench connect the fuel line fitting to the fuel filter.
         1. Position the fuel composition sensor/bracket into place. NOTE: Refer to Fastener Notice in Service Precautions.
         2. Install the fuel composition sensor bracket nuts. Tighten the nuts to 17 N.m (13 lb ft) .
         3. Lower the vehicle.

SOURCE: Chevrolet Suburban 4 Wheel Drive Indicator Lights

Just serviced my own 4x4 Suburban, by buying a 2nd hand encoder motor and replaced the old one, which was trashed by the winter salt. The device is prone to failure since it's made of alluminium and water has an easy time of entering the unit and trashing it.

CAUTION: Abbreviated gratuitous information of how an encoder motor was serviced. If unqualified to deal with repair, seek professional service.
CAUTION: Read at one's own risk.

To replace it, you need to crawl under the vehicle and remove the front drive shaft;

Disconnect the electric harness to the encoder motor, followed by unbolting it.

Take replacement encoder motor and install. There may be an issue with aligning the cogged cam of the transfer case to the encoder motor. If so, the vehicle's 4 wheels will need to be raised off the ground. The engine started, transmission in Park, and using a Vice-Grip® wrench gently rotate cam clockwise approximately 1/16 to 1/8 of an inch, then while set in this position, stop engine. Now attempt to align and attach the encoder motor.

After successfully attaching new encoder motor, attach its wiring loom.
Test vehicle.

SOURCE: My 1999 chevy silverado 1500 four wheel drive

You probably have a bad encoder motor.It is located on the side of the transfer case on the drivers side.It is black.The other problem they had with these was the switch but you have already replaced this so your next thing is the encoder motor.Hope this helps.Good luck.