Hello all. I have a 93 That is not cooperating. So it has the add 4wd system and 4wd is not engaging. I have traced the problem to no vacuum from the engagement vsv. My question is, how do I test the vsv and what actuates the vsv? Is it a switch on the tcase?

 

For all questions, consult The Good Book: http://web.archive.org/web/201204242...26addcontr.pdf

There are two VSVs. Do you have vacuum TO each? The VSVs are driven by 12v; the ground side should be white-black (which you will confirm with your multimeter) and you can run 12v to the "other" side to see if the VSVs work.

 

Ok tests show 12 volts to one when the 4wd lever is in 2wd and 12 volts to the other vsv when I put it in 4wd. Only problem is the 4wd vsv does not apply any vacuum to the line going to the diff when it gets 12v. Bad vsv?

 

If you have vacuum to the VSV, and it has switched voltage, then yes, I would suspect it.

The good news is that this part is only $425 (if you get it online; more from a brick-and-mortar dealer) http://www.toyotapartsoverstock.com/...544035010.html So I would at least check the coil for continuity first (you could have a good coil but bad valve, but one thing at a time).

Running the part number I stumbled on this used part: http://www.ebay.com/itm/like/131636133994?ul_noapp=true&chn=ps&lpid=82 Since it just as old (probably older) than the one you have now, no telling how long it will last. But compared to dealer price you might think of stocking up on this part just in case!