I Have No Start On My 300sdl.. Its Crancking Over But No Start..im Thinking It Might Be The Glow Plug Relay, Not Warming Up The Plugs.. How Can I Check To See If I Have Power On My Plugs? Would A Regular Test Light Do The Job? Thanks..

I think the SDL is turbo and uses pencil type plugs. Let me know if I am wrong. You would hook the positive lead of a VOM to the plug wire and the negative lead to ground. If you have a 12v test light just hook one side to plug wire and other side to ground. This will tell you if you have power. Using the ohm feature and setting it to the lowest value you can pull the block off of the relay and test the plugs themselves. Be sure the wires are still connected to the plugs and test each spot opposite of where the wires come in. Check for about .6 ohm resistance.

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1977 300D Lost coolant while someone else was driving
1983 300D Can't run without oil
1985 300SD (gone but not forgotten)
1990 300TE 4matic Sold
1991 Yamaha Venture
1975 Kawsaki 250 triple
1974 Honda 200CL
1951 8N Ford
2008 Wildfire 650C

A regular test light will do the job, if you only want to verify power.

Glow plug testing.
Glow Plug Testing?

Don't always trust your glow plug indicator light!
Don't always trust your glow plug indicator light!

Glow Plug Relay
Glow Plug Relay

New Glow Plug kit installation. 1978 240D
New Glow Plug kit installation.

Glow plugs link thread
http://www.peachparts.com/shopforum/diesel-discussion/137732-glow-plugs-link-thread.html#post1019018

Replacing Glow Plugs
http://mbdieseldiy.tripod.com/glowplugs.htm

Note: the following link is for a W115
Glow plug timer relay location
Glow plug timer relay location

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1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

Is the GP light on the dash coming on? If not its the 80amp fuse, look in the black box behind the drivers side headlight. Pop the cover off and their is the strip fuse.

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Just Tried Checking For Power. All I Have Is A Test Light.. I Have Power On The Relay... The Fuse Is Not Blown.. But When I Put The Test Light On The Glow Plugs, It Did Not Light Up.. Is It Suppose To Be That Way? My Glow Plug Light On Dash Never Comes Up Either..

Let's just be sure here...

The glow plug relay stays energized for only 20-45 seconds. You should be using the test light at the glow plugs while a helper turns the key, or reach in, turn the key and count to 20 while you test. Any longer, and the relay is off and the tester will not light up.

If you are standing right next to the relay and it's quiet, you should hear a 'click from the relay. If you do, but the test light says you are not getting voltage on any plugs, the fuse is the likely culprit. They can develop a hairline crack but otherwise look OK.

If you don't hear the click, it could be a problem with a contact in the key switch or a bad relay.

Let us know how you're doing.

Did you read the threads I posted?
Here is another one to read post #155 is what you need to see:

wont start for anything!
http://www.peachparts.com/shopforum/diesel-discussion/104222-wont-start-anything-1985-300sd-post725266.html#post725266

ok when i put a testlight on the glow plugs.. are they suppose to light up for the first few seconds after the ignition is turned on...??? meaning am i suppose to see light, power. ? because if so.. im not getting any power on the glow plugs , when i checked with a test light..

thanks hunter for getting back and checking... and thanks to all for all their replies...

the light not coming on doesnt always have to do with the 80amp fuse. i had one bad glow plug and the light didnt come on.

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Yeah, but if all the plugs are dead it is probably the fuse. At least thats what I'd check first.

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

cali,

Do a search on "cabin light". That will give you a quick easy test for the GP.

P E H

That is found in six of the eight links, most are from you.
Not such an easy test idea in intense sunlight, or with bad eyes.
http://www.toontracker.com/magoo/magoo.htm
Where did I put my glasses?

whunter,

Well, you have to admit it is a simple test, easy to do (maybe except in bright sunlight), requires no tools or meters, and nothing to take apart.

Works for me.

P E H