Howdy- I'm out in the boondocks with a 300D (1981) that won't start, likely because the glow plug relay fuse is melted through-and-through.

My question is this- how the hell do I fix it, at least temporarily, with no access to another fuse for at lease 150 miles? I can bridge the terminals with wire, but I don't want to do anything that will fry something irreparably in the pre-glow system.

Any and all advice is welcome, the quicker the better!

thanks,
Randy

1. Call roadside assistance or maybe AAA.
2. Have one overnighted to you.
3. Tell us where you are and maybe there is a forum member nearby to help.
4. You couldn't be lucky enough to have a junk yard nearby could you?
5. Find another diesel owner and see if he happens to have a spare - I always carry one.
6. Push start it.

Good luck.

Len

if you just need a fuse, pull one from a non-essential circuit like the radio, horn, lighter, etc. in a pinch the light aluminum foil on a cigarette pack will temporarily bridge a fuse and will actually burn out well before any serious damage can be done.

Copper wire and lots of it, twisted up.

But really all of Sokoloff's suggestions are better.

I wouldn't have thought cigarette foil would work, but you learn something new every day!

__________________
Ralph

1985 300D Turbo, CA model
248,650 miles and counting...

If you have not got it running yet bridge a heavy wire from the positive terminal of the battery to the side of the fuse on the glow plug side. An old lamp cord with all the ends stripped back and twisted together at both ends should let enough current flow. Hold it on for an appropiate time and see if having someone turning the key will start it. Why I do not particularily like just bridging of the 80 amp fuse is that if you have a shorted glow plug it might weld the contacts together in the relay. You still may have a problem if the jumper does not do it. You may have to figure out if you have a shorted plug and disconnect it before the glow circuit will work. On the otherhand the fuse may have just died of old age. It is open? Or that it is really the glow plugs acting up? If the relay itself has died my bridge will still activate the plugs where bridging a good glow plug fuse will do nothing. Best of luck.

Hi Guys, thanks for the input. I ended up bridging the fuse with some 10 gauge wire and it started immediately. I have no idea why the thing blew in the first place, although I have been experiencing some alternator issues recently (including driving the car with the alternator disconnected from it's belt- don't try this at home, kids). The fuse was wide open; obviously melted in the middle.

And by the way, I'm in Ione, Oregon- if there's a shop forum member anywhere near herer I'll be shocked and amazed.

saludos,
randy

I've got no clue where Ione, OR is.

But, there is a GTG with all the fellows in the NW, including OR and WA, late in April. Check out the sticky thread at the top of the page for info.

Hopefully Randy will come back to this thread and actually read this, just in case this happens to him again!

As many on the Diesel Forum know these high-amp Glow Plug Relay fuses have a way of failing such that it's not always evident [ visually or even with a continuity meter]... i.e. they don't just melt away so such that they are obvious. I believe this is because the failures are often at the molecular level, much like what is called em-brittle-ment. Such failures can manifest themselves so that the car often will not start after running and parking… that is until everything really cools down completely. And we diesel owners know how easily they start if they have been shut down for just a short while.

I discovered that the metal these fuses are made of must be either tin or are tin coated because I found that I could easily solder the broken fuse back together… and thus learned that I could operate the car for an extended period… safely, that is so long as you don’t heavily coat the entire length of the fuse with too much solder when you make such an emergency repair… that is if you can get your hands on a soldering iron or gun. The higher wattage of say a 100W gun is enough for you to make the repair without even having to remove the fuse from the car!

I did this and used the car [ a 1985 300SD with an 80-Amp fuse ] for about a week until I could pick up a new $2 fuse at a Dealer’s parts counter.

Just thought you folks might benefit from this bit of lore !
GoodNight !
Sam

kitchenrat,

The GP relay fuse is an 75 amp fuse. None of the other fuses in the car will work. Light Aluminum foil will burn out quickly with the heavy current drawn by the GP.

P E H

moorerp,

What do you mean the fuse is "likely" burned out? Either it is or it isn't.

If the fuse just has a crack in it as often happens, there is probably nothing wrong in the GP system. But if the fuse is melted, there is a short someplace.

If the fuse is just cracked you can replace the fuse with a piece of copper wire temporarly. If the fuse is melted, you have to find the short and fix it first. It could be a shorted GP.

P E H