Thread: 300TDI What is this warning light for?

It's the glo-plug light - when it goes off the glo-plugs should have reached their operating temp and you can crank the engine to start it. You may find that it starts without waiting for the plugs - that often depends upon the weather.

Originally that lamp was used to indicate that the petrol choke had been pulled out.

Hi Jode,
Thanks for the reply, I just replaced the glow plugs last week, bought a set from Karcraft at silverwater.
I had it running since putting them in, however the light just appeared last night when I went to start it.
So now I'll try and figure out why it's not going out....
Any ideas on what I should be looking for?
Mechanical things are not an issue for me, however electrickery things and I do not get on at all.
Regards,
Mike.

the glow plug relay indication supply contact may have gotten stuck.,

G'day Blknight.aus,
Thanks for the reply.
Where normally would one find this glow plug relay?
Unfortunately the previous owner of this old 300TDI has removed, replaced, hidden, or otherwise stuffed up, pretty much every mechanical, hydraulic & electrical system on it.
Bits and pieces on it/of it are not always where they are supposed to be, nor do they always look like they should!
So as time, enthusiasm and $$$$ come around (unfortunately not much time and $$$$, but plenty of enthusiasm) I have been replacing, adding, repairing & rebuilding it.
On another note, this old beast has far less issues than my 4 month old 90TDCi.
Mike.

from memory its on the firewall just behind the engine

Thanks Blknight,
Unfortunately my 300TDI has 4 relays screwed to the firewall, two of which have the wires cut off.
The wire from no: 4 glow plug goes through the firewall into the bowels of the dash somewhere...
I'm still trying to figure out what all the rest of the stuff on the vehicle is for.
In fact this vehicle has so much added crap that it would give an experienced proctologist nightmares.
I found/pinched a picture of a glow plug relay from EBay.
My vehicle doesn't have one of these specific ones under the bonnet that I can find.

If tour electrics have been butchered then you could do a lot worse than to download/get hold if a rave CD. That has the wiring diagrams in it and as such could be very handy for you.

As Dave says the relay is on the engine side of the bulkhead. It's a long while since I've looked at one, but I seem to remember it has a heavy yellowy/brown wire to/from it.

Either way, chase the wires from the glow plugs, they should work there way back to the relay and then small wires should goto the dash light.

It's all very basic stuff really but you should have a wiring diagram as a means of reference if you aren't sure about these things.

Jon

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Muppet - I'm no wizard either when it comes to volts but you may have a bad earth, which is resulting in the light being 'permanently' on. Once you've found the glo-plug relay then trace its ground wire (typically these are colour-coded black), remove it from whatever part of the chassis it's grounding to, clean that part of the chassis as well as the wire where it connects to it well with emery paper, reconnect and then see if the light goes out after say 30 secs.