I got an 86 westy 4spd, with cruise control installed and working.  My tachometer does not work, when I first picked up the van and was doing nitty gritty cleaning I had the gauge cluster off and the wire for the tach was intact and the connector was snug.  I didn't see any obvious problems with the guage.  I'd like to have a working tach so how can I trouble shoot it?  Can I test the signal wire somehow with the engine running, like with a multimeter or something?  I hate to purchase and install another tach unit only to find out the signal is not there?  Is there a way to test the gauge itself?  Now while I am running without a tach can somebody give me some pointers for shifting without the tach, reading the archives now has me terrified of lugging the engine.  (don't think I'm a complete fool, I've been driving my 5spd jetta since new in 01 and the owners manual indicates to only downshift when things drop below 1500ish, this conditioning is probably not appropriate for the westy).  Specfically here in western pa we have a lot of hills, on a highway what top speed is it safe to drive in 3rd gear?