I just had an '84 here that had the blinking coolant light thing.  I found that the wire to the level sender was broken.  I spliced the wire back together and it fixed the problem.  So, yes an open should make the system blink and on these older vans, the temp needle will peg out.  

I would agree with you that the Bentley is really sketchy about this sender system.  Does anyone know where the "Coolant Level Sensor relay" is located in an '84 Vanagon?  It is not with the rest of the relays, and I couldn't find it after spending some time searching under the dash.  Just curious.

Thanks,
Ken Wilford
John 3:16
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