Glow Plug Light Won't Go Out

[topmarksman]

Hi all,

Not another glow plug problem? sorry, afraid it is.

Yes the light refuses to go out, engine fires up and runs smoothly, but it stays on all the time. I assume if I run it like this it'll drain the battery and burn out the glow plugs.

Not being an electrical whizz, I'll probably try substituting a new relay and maybe a temperature censor. If neither of these work, what else should I be looking for?

Oh one last thing, before the light stopped going out, it was staying on for longer and longer (about 90 secs towards the end) - does this give a clue?

Cheers, Mark

[subiemech85]

add a lite that indicates when the glow plugs are actually on
hook one wire to ground, and the other wire to the bus bar

[vwtopia]

A test light is a good idea. Another thing I do is listen for the relay to click. You should be able to hear the relay click on when you turn the key and then also listen for it to click off. I was amazed at how much longer the relay stayed on after the dash light went off. I first discovered this by a light hooked to the bus bar and ground but then discovered the relay sound clicking off when my test light went off. If I went by my dash light I don't think my glow plugs would ever get hot enough to do any good. Kevin

[subiemech85]

I NEVER hear the relay click, must be the radio, lol

I added a lite that was for a backlite of a aftermarket guage set, putit in the panel for VAG-COM. there was a plug that popped off on the rite side, and it fit perfectly

[topmarksman]

Hi,

Thanks for those tips. yes the relay clicks on and clicks off again and a test light confirms that the current is getting to the glow plugs when it should do, so I guess the problem is with the light on the dash.

So what could be causing the light to stay on, even when the relay has cut the current.

Other thing, has anyone got a wiring diagram they could scan and send to me - point me to where one is on the web.

Cheers