How do I check if the glowplugs are bad with a multimeter?
 

I have a 1980 TD Wagon. It cranks for a while before it starts. I think some the glowplugs are bad but not sure. How do you check if there bad or not with a mutlimeter? Any help will be much appreciated.

first check the fuse for the glow relay, on the sedan its located on the drivers side wheel well hump, or trace the glow plug wires to where they go...

but to test them i belive you unbolt the connection for the glow relay and put an ohm meter, if it reads an insanely high number they are bad...

dieselgiant has the info you need.. with pictures!

http://dieselgiant.com/glowplugrepair.htm

Testing circuit
 

Just pull the black cover off by pulling upward. I recommend testing fuses with a known good test light. Check your test light across the battery before starting( I always do this when starting an electrical test with a test light).

The reason I use a test light instead of DVOM is because you CAN have voltage- but NO current, it takes current to light the bulb. Also, it is good to test with both test light AND a DVOM.

Use the search. You should find countless threads on this topic.