Hello, folks I have a problem with my TC vacuum switch. I have done some troubleshooting, and study a lot of the problems with the treads with this forum. I would like some help if anyone is up to it, all I have in return is a thank you for helping me out. So here goes.
First I have a 97 4x4 blazer, I rebuild the motor and is running fine.
The problem is the four wheel is not ingaging, I have checked the actuator under the battery it is not actuating.
I replace the hoses going to the vacuum supply and to the actuator under the battery tray no workie.
Next I test for vacuum at the vacuum switch, it has 15in. now when i ingage the for wheel the TCCM is actuating the in the TC and the front drive shaft spins.
I measure the vacuum on the other nipple going to the Cable actuator under the battery tray, at the TC vacuum switch it is 4in.
So I replace the TC vacuum switch and retest. I measure the same 15in. on the supply while the 4hi is ingaged and 4in on the cable actuator end.
So this is were I am have the problem, the TCCM seem to work fine, I checked for codes but there was no codes.
The other thing is that while switching the from 4hi to 2hi i have to press the 2hi button four or five times to get it back to 2hi. 4hi and 4low ingage but the vacuum switch is not actuating the cable.

My question is has anyone had problems with the selector plate in the transfer case, Im thinking that the plate is not opening my TC vacuum switch all the way.

 

Sounds like the vacuum lines at the vacuum switch are not connected correctly. The rubber connector only goes on one way, and if it's not correct, the actuator under the battery will not get vacuum.

 

I had fits with my vacuum accuator. I finally bought the posi-lock cable. It is a little expensive($160), but it took me about an hour and a half to install, and it works really well. I definately do not regret getting it, as compared to all the trouble shooting and trial and error, and head ache I would have had trying to fix the vacuum actuator system.

 

I did my own posi lock for under $40! I using it frequently and have not had a single issue yet. Check out the first few pages of my build thread for more info and feel free o ask questions if you have any.

 

Thank you folks for your help, will look up the posi lock also will check the vacuum hoses at the vacuum switch. Be cool and have a great day.