VARIJANTA 1
http://www.ngk-dpower.com/index.php?id=31&L=2
VARIJANTA 2 kućna varijanta uz malo više truda
Testing glow plugs is easy and can be done with them still installed in the engine. Just disconnect the wire going to each glow plug. Connect a test light to the POSITIVE (+) battery terminal and touch the point of the test light to each glow plug terminal. If the light lights, it's good. If it doesn't, it's bad and needs to be replaced. Do you replace just the bad one or all of them? My opinion is that if one went bad, then the rest are not too far behind. So I recommend replacing all of them at the same time. I would replace, at the very least, all of the glow plugs on the same side."
i vrlo važna stvar kad ode jedan grejač,menjaju se svi jer se može očekivati da će početi otkazivati redom,dobija se pouzdan auto u svakom trenutku i štedi novac za ruke(jedino ako niste automehaničar koji ne ceni svoje vreme) jer kad se promene i stave kvalitetni,čitaj originalni grejači mirni ste najmanje dve godine,često i mnogo duže...