Diff Lock Vacuum Problem

[7thing3]

I was having trouble getting my diff lock to engage. The decoupler engaged with no problem, except when I had the knob out for the diff lock, which led me to believe it was a vacuum line problem. Checked all the vacuum components and cleaned out the check valve. When I ran a vacuum line directly to the actuator bypassing the valve switch it engaged without a problem.

Turned out to be an easy solution--I swapped the 2 vacuum valve switches behind the console and now both work fine. Maybe I had a kinked line or the new switch that came with the decoupler is not full of 25 years of gunk. Either way, now both work and that's one less thing I have to worry about. Not sure if I will ever need the rear diff lock but it's nice to know it works if I do need it.

I am posting as maybe this will help someone else. The first step I would take if you are having issues is to run a vacuum line directly ahead of the check valve to the actuator.
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'73 Thing--Ted
'77 Super Beetle Convertible
'87 Vanagon GL Syncro
'84 Mercedes 280 CE