I have a 1984 300SD and the Glow Plug Light is not coming on, the buzzer is working fine and the battery indicates a voltage drop when the glow plugs are on but the bulb will not light. I check continuity across the bulb and it is ok. I swapped it with the bulb in the Hi beam indicator and it was ok but the replacement from the Hi beam indicator which worked in the Hi beam indicator side does not work on the glow plug side. Suggestions welcome.

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Gary
OBK #37

Sounds like a bad glow plug. http://www.peachparts.com/shopforum/showthread.php?t=263393

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92 300D 2.5L OM602 OBK #59

I'm betting #1 glowplug is out. Ohm them all out.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

I just went through this. It was easy in my case. I only had one plug that had "higher than normal" resistance. #3 was the problem in my case. It could be any of them. There are some other things to check too. Here is that thread:

http://www.peachparts.com/shopforum/showthread.php?t=259616&highlight=glow+plug+light

Follow the tutorial over at DG. The system is pretty easy to troubleshoot.

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AJ

1985 300D (SOLD)

I personally think its easier to ohm out the glow plugs than remove the instrument panel. LOL

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92 300D 2.5L OM602 OBK #59

That is why I posted... Takes about 2 minutes to check the plugs at the "plug".

That includes unlocking the car, opening the hood, turning on the meter, removing the plug access cover, etc... You get the picture...

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AJ

1985 300D (SOLD)

Well , I checked the bulb and it was ok, tomorrow I will do the GP's. Where can I purchase a GP reaming tool?

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Gary
OBK #37

you can rent one here : http://www.peachparts.com/shopforum/showthread.php?t=126728

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92 300D 2.5L OM602 OBK #59

You can also use a drill bit, forgot the size off the top of my head. Worked great for me, just a bit more cumbersome since you can't thread it in like the reamer.

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

I forgot to report back on what the problem was. No. 1 GP read 0 ohms and the wire was good so I replaced the GP (NGK) with Bosch out of my parts car. Thank goodness for parts cars the previous owner, of the parts car, must have changed them out just before I got the car. The Bosch GPs are still shiny just a little oily.
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Gary
OBK #37

You want it to read less than 1 ohm, so glow plug #1 is ok, there was no need to replace it.

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1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg

Do all of your other dash lights come on? Mine didn't, and all I did was connect a ground wire and viola it came back.

Just count to 15 and start it. I have been doing that for years and it works. My GP light is out in 2 seconds with new Bosh plugs, also you can use the seat belt buzzer to time them.

Don't laugh just try it.
Robert