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General Information => Troubleshooting => Topic started by: rabbitman on April 04, 2008, 06:06:17 pm

Title: Glow plug light comes on while driving
Post by: rabbitman on April 04, 2008, 06:06:17 pm: I have a problem, starting a few days ago my glow plug light started flickering and now quite frequently it comes on steady. This is on a mk1 so there's not supposed to be a water sensor. Is this a bad GP relay? The glow plugs and relay act normal when it's cold started, you know, light goes out and 5-10 seconds later the relay clicks. I don't hear the relay click when the light comes on while I'm driving but there's road, wind, engine noise and CD playin' to drown it out. :lol: Anyways, when problems are had, this is the place to go. :)

PS. It always scares me when the light comes on 'cause I've heard of the plugs burning out :shock:
Title: Glow plug light comes on while driving
Post by: Quantum TD on April 04, 2008, 06:45:32 pm: Either:
1) bad relay
2) bad sensor
3) water on the fuse panel
4) bad contacts on main glow fuse

Good luck
Title: Glow plug light comes on while driving
Post by: TPW on April 04, 2008, 07:56:50 pm: The light comes on when the relay connects to a ground. If the wire between the relay and the light has a bare spot that grounds out, that could also cause the light to turn on.
Title: Glow plug light comes on while driving
Post by: subsonic on April 04, 2008, 08:59:47 pm: Water fuel seperator. If you still have it, it's time to drain.
Title: Glow plug light comes on while driving
Post by: fatmobile on April 04, 2008, 11:18:28 pm: I've had the glow plug power wire connector get loose,
one of the fat red wires on the positive post of the battery goes to the glow plugs, the lug was loose.
Title: Glow plug light comes on while driving
Post by: burn_your_money on April 05, 2008, 06:41:55 am: Quote from: "subsonic"
Water fuel seperator. If you still have it, it's time to drain.

This one happened to my old jetta
Title: Glow plug light comes on while driving
Post by: rabbitman on April 06, 2008, 10:15:13 am: Wow, you guy are really on top of things :D So far I've swapped the wires on the temp sensors and the guage works like normal and the GP light still flickers sometimes.
How do I get to the water seperator? I've looked up above the right rear tire and I can't see anything and it's not under the seat......at least it's not obvious.

Ps. We went snowmachining yesterday at the only place that still has snow......wow that's fun, my poor 'machine is havin' a rough life. :twisted:
Title: Glow plug light comes on while driving
Post by: subsonic on April 06, 2008, 12:09:32 pm: Right side, in front of rear tire, up under the body.
Title: Glow plug light comes on while driving
Post by: blkboostedtruck on April 06, 2008, 12:21:08 pm: he has a MK1 it should not have a seperator! only seperates water in the filter under the hood! am i right?
Duane
Title: Glow plug light comes on while driving
Post by: subsonic on April 06, 2008, 12:38:44 pm: Not sure, you may be right. My bentley only goes back to 85. Did the mk1 have a high water indicator?
Title: Glow plug light comes on while driving
Post by: rabbitman on April 06, 2008, 02:38:57 pm: I just looked in my bentley and there is a gravity valve and a expansion tank, wasn't sure if the expansion tank doubled as a water drain but it doesn't say anything about it. I can't find it anyways. :roll:
Title: Glow plug light comes on while driving
Post by: burn_your_money on April 06, 2008, 03:37:11 pm: You're right Duane. There is no water separator, only the fuel filter.
Title: Glow plug light comes on while driving
Post by: Vincent Waldon on April 06, 2008, 09:41:31 pm: If you had one, it would look like this:

(http://i197.photobucket.com/albums/aa85/vwaldon/Waterseperator.jpg)
Title: Glow plug light comes on while driving
Post by: zukgod1 on April 07, 2008, 07:22:50 am: I just had this happen this morning, light flicker but very dim and then it stayed on but still very dim. Pulled the relay and still on.

I'm kinda leaning towards the 2 wires that used to go to the water separator. I just cut them off when I removed it. I suppose there could be moisture causing them to conduct a tad??

I'm at work now so I wont be able to look till tonight :(

Anyone have a suggestion before I start looking?
Title: Glow plug light comes on while driving
Post by: Vincent Waldon on April 07, 2008, 09:04:40 am: Quote from: "zukgod1"
I just had this happen this morning, light flicker but very dim and then it stayed on but still very dim. Pulled the relay and still on.

I'm kinda leaning towards the 2 wires that used to go to the water separator. I just cut them off when I removed it. I suppose there could be moisture causing them to conduct a tad??

BTDT, about a hundred times... the PO had deleted the wiring to the water separator but water seeped into the electrical tape... little bitta water, some road salt... after all, those leads do go straight to water detection probes so it's a sensitive circuit.

Cut the wires back a bit, retaped and isolated them from each other by a few inches... no more dim and/or flickering glowplug light.
Title: Glow plug light comes on while driving
Post by: zukgod1 on April 07, 2008, 09:49:43 am: Sweet, thanks Vince..
I think I'll just pull them up through the trunk and eliminate the problem that way.
Title: Glow plug light comes on while driving
Post by: rabbitman on April 07, 2008, 10:48:46 am: Well problem solved, Vince, I definitely don't have that under there, nice pic though. A few days ago I put in some 1 gauge starter cable, which btw is a very good thing to do as it cranks much faster now, and I also used a fatter ground wire for the body.......and :oops: I forgot to tighten it. :roll: Anyways I fixed that and no more annoying light. The funny thing is that my CD player worked fine and it's grounded to the body so it should've cut out a lot but it worked fine.

Ps. The best way to fix a problem is to think back to what I recently tried fixing and the problem and my repair are usually related. Anyways thanks everyone!!!!