Glowplug light 'glowing'

nick · Unread post by **nick** » 19 Sep 2004, 18:42

Bit of a strange problem this, and not one I've heard of on a Xantia before. This is on a '97 1.9TD.
After switching off the engine, the glowplug warning light 'glows' faintly for several minutes until it gradually fades and goes out. This appears to be related to the battery charge level – if a trickle charger is connected to the battery it also causes the light to glow until the charger is disconnected.
Its not exactly urgent, its been doing this since I bought the car over 4 years ago (for all I know it could have been doing this since it was new!) and doesn’t seem to cause any other problems. I’m just curious as to why it does it. Possibilities I thought of were either a faulty glowplug control unit, or perhaps a bad earth connection causing something else to earth through the warning light?
Any other suggestions?
Cheers,
Nick

AndersDK · Unread post by **AndersDK** » 19 Sep 2004, 19:20

That's odd.
The glowplug timer lamp is earthed one side within the instrument panel, and is feeded a +12V from the glowtimer unit as long as the timing occurs.
This means the timer circuit itself is "leaking" some smallish voltage to the timer lamp, when it's not supposed to do so.
Could be a simple corrosion problem, 2 nearby connectors on the timer is leaking a weak voltage over to the lamp connection.
Either way, have it investigated before it comes to an unpleasant service stop, just when you need the car the most.

nick · Unread post by **nick** » 19 Sep 2004, 20:47

Thanks Anders.
I've just removed the timer unit from the car, re-connected the battery, and the lamp still glows even with the timer completely disconnnected!
I've checked the connector plug and there's no obvious corrosion or damage, so it looks as though there's a problem with the wiring elsewhere.

bxbodger · Unread post by **bxbodger** » 19 Sep 2004, 22:27

You could try pulling fuses circuit by circuit and see if this makes it go out- it may narrow the field of culprits down a bit.

mseymour · Unread post by **mseymour** » 20 Sep 2004, 14:33

No idea about Xantia electrics, but I had similar strange behaviour from a cavalier TD couple of years ago. I ignored it until after a wash the car wouldn't start and the electrics were really strange with the dash lights behaving very oddly. A tow to the auto electrician later and it turned out to be a failed earth connection to the engine block. You could have something similar.

nick · Unread post by **nick** » 20 Sep 2004, 17:13

Thanks for the suggestions, I'll try removing the fuses and see if I can pin the problem on a particular circuit.

derekjl57 · Unread post by **derekjl57** » 20 Sep 2004, 17:53

I'd check the engine earth strap first, what appeared to be a good connection on mine turned out not to be, and resulted in many strange quirks. Eventually, the engine refused to start (even more oddly, on the second start of the day, having started perfectly only 15mins earlier), resulting in a call out to the RAC man. I'd only had the car 48 hours....

nick · Unread post by **nick** » 20 Sep 2004, 22:29

I do wonder if its related to a problem I had with the car when I first bought it. The battery was in a very poor condition and had been 'gassing' for some time. Result was that acid had been dribbling down the side of the battery, all over the battery tray and below. I removed the old battery, cleaned the area down with a pressure washer and washing soda, protected the metal where the paint had been burnt off, then fitted a new battery. It is quite possible that some unseen damage had been caused to some of the electrical connections, including maybe the earth strap. The connections right next the battery are fine, but I don't know how far the acid got.....

1110 · Unread post by **1110** » 23 Sep 2004, 02:14

almost certainly an earth problem - when i converted my zx 1.8i to turbo diesel i missed an earth connector behing the dash when i changed the dash loom. it made certain bulbs light dimly, even with the ignition off, conecting the earth made everything come to life - i would put money on it being an earth if i put money on things and i dont.