[Vwdiesel] Glow Plug relay troubles

MLightner mikel at buncombe.main.nc.us
Wed Jan 31 20:36:30 EST 2007

Date: Sun, 28 Jan 2007 15:44:09 -0800 (PST)
From: David Cook <vwdieselbunny at yahoo.com>
Subject: [Vwdiesel] Glow Plug Relay Weirdness
To: audi-vw-diesels at yahoogroups.com, diesel list <vwdiesel at vwfans.com>
Message-ID: <141651.49875.qm at web51304.mail.yahoo.com>
Content-Type: text/plain; charset=iso-8859-1

(from an earlier post)

>I installed my glow plugs this afternoon, as well as
>finally getting the cold start handle in!  Woo Hoo,
>the conversion is finally complete after two plus

What kind of conversion is this?  (sorry, I've been reading the archives alot, but been 
skipping around, can't yet keep the who, what or when straight : )

>Anyway, the reason the GPs burned out is that the
>relay will very quickly trigger on and off, causing
>the indicator light to flash and the GPs to get power
>and have it cut off very quickly over and over.  

When you say indicator light, do you mean the one in the cluster, or have you added one 
that's hooked only to the glow plugs and therefore comes on only when the glow plugs do?

>It happens so fast it sounds like a cicadia is under the
>dash buzzing or something.

>My theory on why this was happening is that the
>wiretap I did to get the signal to turn the plugs on
>from the ignition switch was bad.  Today, I redid that
>connection and it still did it once while driving.

Not knowing the particulars of the circuit you're trying to get straightened out, it's
only possible to guess;  are there other accessories that are fed by the wire you tapped 
into that give you good reason to believe that the contacts in the ignition switch that 
feed the circuit are in good shape?

>I also noticed that sometimes when the car is started,
>the indicator light will flash, though I can't hear or
>feel the relay clicking.  Revving it so the alternator
>will start usually makes that stop, but not every

Hard to say if it's related or just coincidence - from a more recent post of yours:

>I still haven't found the source of the problems with
>my glow plug relay going crazy and thinking that the
>key is turned on and off quickly while driving.

Argument for possibly faulty ignition switch contacts 

>Up until now, I would just reach down and unplug the
>relay when it started doing that, but that was getting

>So, I bought a simple on-off switch, and wired that
>into the relay's ground wire.

>Now, the relay won't click like before.  However, the
>indicator light stays on, even with the engine running
>and through a whole drive.

>The light kind of flickers, but is basically on the
>whole time.

The temp sensor wire came off on mine once and the glow light would stay lit till I 
turned the key (I never waited longer than 15 or 20 seconds).

Can you draw the circuit out?  Then, go back and trace each wire in the car and compare/
doublecheck with the schematic.  Sorry if it's not much help, that's all I can think of
at the moment. 


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