Check the sub harness between the GP Relay and the GP's , especially closely where it makes bends and goes through supports or metal ~ there's prolly a bit of bare wire that occasionally touches a grounding point .
Most of the time when the GP Safety Fuse blows , you have an internally shorted glow plug .
IIRC , there's a P-A-P Yard near you and if the W-116/123/126 junker's relay looks the same, it is , they only charged me $15 or so for the last several I bought when my Coupe had similar issues , I tested them all and one was bad , the others worked fine to I tossed out my old relay and the one bad junkyard relay then ever so carefully stashed my spare relays and haven't seen them since else I'd send you a spare known good one for testing fitting .
-Nate
Chip wrote :
>
> I have a 1982 300CD turbo. About a year ago my glow plug relay fuse blew for the first time. It has since blown a half dozen times. Simple to replace, it is an 80 Amp bridge fuse.
>
> I had suspected I had a glow plug that was the culprit but I did a VOM test a few days ago and found all of my glow plugs are good.
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> Any idea what gives on this. Obviously when the relay fuse blows there is not starting the car. I did notice when this first started that the glow plug light would only come on for a second or so, mostly in the middle of the sequence, meaning that the glow plug indicator did not light when the key first turned, but come on after a second or two.
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> I have and can continue to periodically replace the fuse, but I would like to get to the bottom of this.
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> Chip
> Houston
>