OK viewed several tutorials on the location of the vacuum lines on the transfer case. Cannot find any on the transfer case .... is it possible there is another way the 4 wheel drive engages??? Dash lights blink in both high and low range ... every thing seems as before it stopped working.

Just asking ... is vacuum actuation, on top of the transfer case is the only method of engaging 4 wheel drive.

Thanks
Dom

 

The transfer case is shifted with an encoder motor, (electric motor) on the driver side of the case. When it shifts, linkage inside the case operates a vacuum switch next to the encoder motor. The vacuum switch applies vacuum to an actuator under the battery tray. The actuator engages the right front axle with the front differential, and you're in 4WD. In the image below, you can see the encoder motor inboard of the front driveshaft connection to the case. Slightly above it you can see the three vacuum ports on the vacuum switch:





One vacuum line comes from under the hood and should have manifold vacuum when the engine is running. The second line goes up a few inches to a Tee that connects to the transfer case vent, (also visible in the image). From there it runs up the transmission dipstick tube and is zip tied to the tube and has a filter on the end. The third line goes to the actuator under the battery tray.

 

Thanks Chuck take a look at these photos. Your thoughts??? to me they just don't look the same. Thanks for the prompt reply Dom


Transfer casr Jimmy 1_zpsbmbwnsul.jpg Photo by ddominik | Photobucket

Transfer casr Jimmy 3_zps7r7mwskq.jpg Photo by ddominik | Photobucket

 

There was an AWD option for the '95-'97 s-series Blazer that used a Borg-Warner transfer case that was always engaged, splitting power 35/65 front/rear if I remember correctly. In those vehicles, the front axle would not have the disconnect mechanism as the front axle would need to be engaged all of the time for proper operation.

However, based on the pictures you provided, you have the far more common 4WD option. Those pictures only show the front axle which has the disconnect system shown. The vacuum line controlling the actuator that can be found on the other end of the cable shown in your pictures will lead back down to the transfer case which is located behind the transmission and will look like the picture that Chuck posted.

 

DUH!!! Forehead slap ... leave it to a retired engineer to look in the wrong place LOL. THANK YOU very much. My skined knuckles are ready for round 2.

Dom (TNNOMAD)