Like the title says my 4wd will not engage. The transfer case is working properly and the 4wd light is working. I have tried to switch the vacuum lines at the vsv. I am getting vacuum at the vsv. But switching vacuum lines did nothing. I am at a loss. I have searched everywhere and can not find any info on the add system on the 1st gen 4runners. I am sure I am not the first one with this problem, and if anyone can help you guys can. Thanks in advance for any help that is provided.

 

Can you manually engage the actuator with vacuum pump?

 

To be honest I wouldn't even go as far as diagnosing the problem. I would do a manual hub install and call it good.