Thanks for that comprehensive explanation.

--Gnarlie

Entity Jeffrey Earl spoke thus:

> To learn more (perhaps more than you really wanted to
> know) about the VW diesel glow-system, visit Roger
> Brown's excellent page:
>
> http://4crawler.cruiserpages.com/Diesel/CheapTricks/GlowPlugs.shtml
>
> From whence I quote:
> "So you have the little yellow glow plug LED on the
> dash, why do you need another glow plug light?
> Actually, the LED on the dash has nothing to do with
> the glow plugs. Its just an output from one part of
> the glow plug relay, which takes the temperature
> sender input and produces a delay to let the glow
> plugs reach the proper operating temperature. The glow
> plugs themselves are powered by a relay which is
> operated by a different part of the relay circuit and
> they generally stay on for a time after the LED goes
> out. If the coolant temperature is warm enough, the
> glow plugs and LED won't be turned on at all in the
> "glow" position of the ignition switch. However, the
> glow plugs are always turned on whenever the starter
> is operating, regardless of temperature.
>
> "By running a wire off the glow plug bus bar to a
> light on the dash, it will be possible to observe when
> power is actually reaching the glow plugs directly.
> This indicator would be useful to diagnose a number of
> glow plug problems."
>
> IIRC, the Bentley specifies that--assuming a cold
> engine--the glow plugs should continue to glow for 30
> seconds AFTER the engine is running, although the dash
> indicator will have gone out long before.
>
> Jeffrey Earl
> 1983 diesel Westfalia "Vanasazi"