Glow Plug (GP) not working

[WolfieG]

I thought I'd post about a problem we just had with our '98 NB TDI, and the VERY simple solution.

For the last couple of days we've been hearing a clicking/racheting type noise when the ignition key is turned on, but not to the start position. The battery is strong, so we knew it wasn't that.

Then we noticed that sometimes this noise was accompanied by the glow plug light flickering on and off.

We've also had the car spontaneous shut off while cruising down the highway (not related to bumps in the road either) and then (b/c it's a 5 spd) just fire right back up after a half second 'stall'.

Last night the car failed to even turn the glow plug light(and consequently glow plugs) on at all.

After doing some reading here and on TDIClub.org I started to suspect either the Power Supply Relay (109) or the GP Relay (180). Given the spontaneous shut down, I was leaning more towards it being 109... which is also way easier to get to.

I jiggled 109 around a bit (located under dash, above the pedals) and was able to get the glow plug light to come on intermittently. I took it out and cleaned the leads (steel wool and De-Oxit), popped it back in, and the car starts.

However, the relay does have a pretty nasty burnt electrical odor to it, so I'm grabbing a new one to replace it.

Had we taken this to a dealership I'm sure we would have ended up with new GPs, GP Harness, and GP Relay... and then eventually found the Power Supply relay was the problem.

I hope this helps others out there self diagnose a problem.

[Yello_jellybean]

Thanks WolfieG. I will make note of this, in case this happens to me in the future.