Zdenek
New member
Some systems use 6V glow plugs on a 12V for faster heating. The power is modulated on and off to prevent melting the 6V glow plug internals on 12V.
Steady 12V on 6V glow plugs with a manual switch would be trouble.
I believe these are 12 V plugs. The relay stays on continuously for a time determined by the computer and based on engine temp.