Author Topic: Glow plug issues (Read 5045 times)

webman · « **on:** June 25, 2008, 06:20:38 pm »

I recently picked up a 91 Jetta that is having problems with the glow plugs. I am having two problems, and they are likley related.

1) The glow plug indicator on the dash does not come on, but I believe the LED is good. I did a test between L ad 85 on the glow plug connector, but I did not show any voltage.

2) The glow plugs come on and appear to stay on. I waited 45 sec and there was still power showing at the glow plugs.

I have replaced the relay with a new one, but still have both problems.

Any ideas where I should start looking? I have tried all the tests in the Bently manual for the glow plugs, but not sure where the problems are. Also, it mentions a fuse for the indicator, but I don't see one labeled on the fuse panel.

burn_your_money · « **Reply #1 on:** June 25, 2008, 07:13:44 pm »

I'd suspect the temp sensor myself.

You can jump the glow plug light through the glow plug relay socket.

CoolAirVw · « **Reply #2 on:** June 25, 2008, 07:30:25 pm »

VWCaddy's page has some of the best info I've seen on how the glow plug system works.

http://www.4crawler.com/Diesel/GlowPlug.shtml

Heres another.

http://www.cs.rochester.edu/u/jag/vw/engine/glowplugs/glowplugs.html

webman · « **Reply #3 on:** June 25, 2008, 07:42:51 pm »

Quote from: "burn_your_money"

You can jump the glow plug light through the glow plug relay socket.

So do I go from power to the L terminal?

burn_your_money · « **Reply #4 on:** June 26, 2008, 04:55:07 am »

http://www.4crawler.com/Diesel/CheapTricks/Images/GlowPlug_05.jpg

Yes

webman · « **Reply #5 on:** June 26, 2008, 07:57:37 pm »

Which temp sensor is for the glow plugs? The one on the top or side?