hello i have a 98 blazer that does not seem to be going into 4 wheel drive. new actucator,the push button lights change ,the transmission seems to be changes ,i can hear something in the dash changing .the transfer case does not seem like it is getting changed. how do i check to see if the cable is being moved at the transfer case?i havent check the for vacuum leak yet. how much vacuum should the actucator have?where does the vacuum comefrom?what should i being looking for to get this issue solved or corrected. thank you for your help

 

Could have oil in your vacuum line from tranny to actuator. Fairly common. Look on yop of your t case and will be 3 hoses coming out of the same spot, one of them goes to your actuator. If there`s fluid in it you have other problems. Maybe switch that they all plug into or a bad seal filling up your t case. Good luck

 

The vac actuator is under the battery tray. You can inspect it from there. The system is so prone to failure that two company's make manually operated replacements. They are Posi-lock and Alloy.
To see how and if its working is a real pain. You need to take the battery and tray out so you can get and eyeball on it.
Lay the battery back up there get it started. Then you take the battery out with it running. Connect the battery back with jumper cables to prevent damage to the VR & diodes in the alternator. Push the button in the truck and see if it "sucks in". If it does not take the hose off. Stick the end on your tongue. If you can feel it the actuator diaphragm is bad. It takes very little vacuum to make the system work. If there is no vacuum in the line you have another problem. Come back and we can pick it up from there.
Let us know one way or the other.

https://blazerforum.com/forum/tech-a...ill-help-7180/

 

One thing you might try is to put the truck in 4HI and then jack up just the right front wheel. Try and turn the wheel when it's in the air. If it turns then your front axle isn't properly locking. If it doesn't turn then the front axle is properly locking. That will tell you if the cable is pulling properly from the actuator under the battery tray. Once you've done that test you can move on to some of the other diagnostic tests posted on the Forum. The thread https://blazerforum.com/forum/tech-a...ill-help-7180/ is a good place to start.

 

i put the switch (push button ) into 4hi jack up the front end and the wheels spun with blazer running and shut off.that would tell me that the actuator or cable is bad correct if i have vacuum. i looked real guick but didnt see those three vacuum hose yet . this weekend i will oull battery tray out and follow that vaccum line to the actuator to check vacuum. i did see one post where a gentlemen posted about a mod is that something i could do to limit my problem. thanks