Glow plug relay not turning on?
 

i check that there is power going to it and power on both sides of the fuseable link. all fuses in the fuse box are good. i also swapped out a known good relay and still doesn't work. what else can i check?

thanks.

You could try posting the year and model or fill in your signature.

woops, I meant to.

1984 300sd.

thanks.

I would try a new 80 amp strip fuse. They are known to crack and cause intermittent starting problems.

i already multi-metered both sides and there is power. i also swapped the glow plug relay out for a known working unit. i am going to check the ground today.

I understand that, but those fuses develop hair line cracks. They can test OK, but not allow enough power through for the car to start. If you do a search you can find several instances of this occurring. I keep a new one taped inside my glovebox for the next time mine cracks.

http://www.peachparts.com/search.htm?cx=015238323195528004774%3A_wneywo5nvm&cof=FORID%3A9&q=80+amp+fuse+crack&sa=Search&siteur l=www.peachparts.com%252Fshopforum%252Findex.php

http://dieselgiant.com/glowplugrepair.htm

What part of this isn't working?

the relay was not activating, all glow plugs tested good.

i added my own ground and it still didnt work? so i swapped it out for another one. and now i was only getting 10v coming out of it. but at least it was turning on. what i did was open the case and i noticed that there was some corrosion around point connections, so i filed them clean, now i get 12v out. glow plug light comes on and car fires right up.

thanks.