[Vwdiesel] Dying Glow Plug Relays???

Mark Shepherd mark at shepher.fsnet.co.uk
Sat Aug 6 09:20:33 EDT 2005

Hi Paul are you saying that the relays are being killed?.
 Can't see as harness corrosion would do that because:
Relay resistance is near zero through switched power to GP's which
have a  combined resistance of 1/4  ohm ish. So any corrosion
increases the resistance and increases the mismatch from battery
supply internal resistance and so decreases power transfer...
Can it be that your voltage regulation is running too high and
overloading the relay?


Hi everyone,

I have a 2000 Golf TDI. The "original" glow plug relay
failed 2 months ago.

Installed the "first new" glow plug relay, and that
fixed the C.E.L.  -- for 3 weeks.  After 3 weeks, got
another check engine light.   Vag-Com gave a  "16764 -
Glow Plug/Heater Circuit Malfunction" error, just like
the "original" relay.

Checked all the glow plugs and the wiring.  Only thing
left to try was another glow plug relay.

The dealer replaced the "first new" relay under warranty.
The "second new" GP relay fixed the check engine light --
for 3 weeks.

The  "second new" glow plug relay is throwing a check
engine light!  It's the same code as before -- "16764 -
Glow Plug/Heater (Q6) Circuit Malfunction P 0380 - 35-10
  - Intermittent".  It also lasted about 3 weeks.

Removed and checked the glow plugs - nice, even orange
glow. The connections from plugs to the relay check OK.

The glow plugs that are installed are labelled "Beru

1.  The relay clicks on when the ignition switch is turned
     on, and clicks off immediately.  Get a short blink on
     a test light.

2.  Disconnected the coolant temperature sensor. Relay
     still clicks briefly, like before. Glowplug warning
     light stays on longer, like it should.

3.  Checked the wiring under the hood. There's continuity
     to the relay.  Everything seems clean and tight.

4.  Removed and checked the glow plugs - nice, even orange

5.  Checked glow plug fuse - tests OK.

6.  Ran out of other things to try.  The Bentley book and
     service CDROM aren't any more help now.

Changing relays seems to fix the problem for 3 weeks at a
time, but will become kind of expensive at $125 each.

What am I missing?



2000 Golf TDI Manual


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