I started the car today and noticed the glow plug light stayed on after the engine started. I turned the car off. I started it again but the light did not turn on. Only after the car started did it come on. It stayed on for about a minute then finally turned off.

Is this a symptom of a bad relay or fuse?

I pulled the glow plug relay out to check the fuse but I do not see it on this one. See pics...

please help. Is the fuse "inside" the box ?

Attached Thumbnails

   

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Ben
1987 190d 2.5Turbo

I have a 300 SDL but should be in the same place. It is on driver's finder towards the front in the ABS area. Should see the wire from the glow plug harness entering it.

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1986 300 SDL - rolling parts car and test bed.
1987 300 SDL - semi daily driver.
1977 U1000 Unimog
2007 Ram 2500 6.7l

I'm not sure about your car, but my '96 has internal fuses.

Check your plugs first. If they're all good, the relay is probably bad.

btw it is in a box but not that box

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1986 300 SDL - rolling parts car and test bed.
1987 300 SDL - semi daily driver.
1977 U1000 Unimog
2007 Ram 2500 6.7l

After doing some research, it looks like the symptoms point towards a bad glow plug.

The glow plug light does not come on. Only after the engine starts does the glow plug light come on. This a self diagnosis feature of the relay. There is really nothing wrong with the relay.

Is this correct? Thanks in advance. I appreciate the help.

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Ben
1987 190d 2.5Turbo

Easy to test the plugs or just replace them. They are a wear item and if you don't know when they were last replaced then do it. If they work at all then not the relay.

Go ahead and replace that fuse link too. It will fail. A lot of amperage goes through it and it heat cycles eventually fatiguing the metal until it fails.

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1986 300 SDL - rolling parts car and test bed.
1987 300 SDL - semi daily driver.
1977 U1000 Unimog
2007 Ram 2500 6.7l

If the Engine with the Glow Plug issues has an Aluminum Cylinder Head and you need to remove any; I would consult the DIY section on how to reduce the chances of snapping of the Hex heads on the Glow Plugs.

DIY Repair Links
http://www.peachparts.com/shopforum/diy-links-parts-category/

http://www.peachparts.com/Wikka/DoItYourSelf

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84 300D, 82 Volvo 244Gl Diesel

BH,

The Pre-Glow Relay's Instrument Cluster (Yellow) light will/should come on as
soon as you turn the Key to the "Glow" position.


The Glow Plug relay you've pictured DOES NOT HAVE A
FUSE (80 Amp).
It Has ELECTRONIC sensing protection.
In case of a Dead Short or other dangerous Electric
Anomaly,the Relay automatically Dis-Connects itself.
,Until the Fault is Rectified.
All OM602.962 and some OM603.XXX engines came with
these Intelligent Relays.

And Yes the Relay's actions are telling you one or more
GP(s) are Bad.

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'84 300SD sold
124.128

Thanks Compress.

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Ben
1987 190d 2.5Turbo