[urq] Overtemperature Warning Light

[Alan Pemberton]

Car is 1985 WX.  I've just finished reassembly after repair of two broken
exhaust manifold studs on No 2 cylinder and consequent gasket blowout.  The
good news is that the engine runs.  The only issue is a flashing high
coolant temperature warning on the dash even when the engine is completely
cold.  The sender appears to be the one in the block to top hose connector
with a two pin plug.  This was removed for cleaning and reinstalled.

Having trouble understanding the Bentley.  There are two wires as shown on
page 97.143 tracks 80 and 81 - one is blue/yellow and the other blue/brown.
The blue brown wire is part of the coolant low temperature indicator system
and this is working - blue light is on with engine cold.  The blue/yellow is
shown continuing on track 243 which is blue white and connected to the air
conditioning compressor clutch control unit? The indicator light is shown as
K28 on track 185.

The switch is open to ground at both pins with the plug disconnected.  With
the ignition on and plug removed, there is 12 V on the blue/yellow wire.
The red warning continues to flash but the blue light goes out.  I assume
that the high temperature switch is normally open and closes, completing the
circuit to ground, if the coolant temperature is too high.  However, if this
was the case, removing the plug should stop the flashing.

Can anyone steer me in the right direction?

TIA

Alan Pemberton
85 urq (Canadian)