Date: Fri, 29 Aug 1997 18:11:42 +1000
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: Jack Newton <johnn@TRIODE.NET.AU>
Subject: Re: Coolant warning light trouble
Johan Nyberg writes:
> I have a problem with the coolant level warning light. Sometimes it goes
on
> flashing for a very long time (5 minutes or so) after the engine is
started
>'
Hi Johan
It seems to me as if you have a bad electrical contact between the sensor
and the controller in relay position #3. Although Bentley is pretty
silent on this sensor I believe its modus operandum is:
A voltage across the sensor's two metal prongs which are immersed in
coolant
sees a fairly high resistance which the controller interprets as "Coolant
Present".
When the coolant level drops, the resistance seen by the sensor's two
prongs, which are not now immersed, is
infinite i.e. open circuit. The controller interprets this as "LOW
COOLANT'
and, after an interval, the warning light starts to flash. The time
interval is set by a circuit in the controller.
It follows from this that if the connections are bad an open circuit may
occur which the controller interprets as LOW COOLANT and, after a few
seconds delay, the light will flash, this is a fail safe feature of the
circuit.
I would suggest you check the sensor and controller for bad connections
with the ignition off. The fact that wiggling the wires at the connector
changes the circuit's behaviour also indicates that the problem is a bad
connector (I always suspect the connectors). Clean the male and female
contacts and making sure that the sockets are not slack.
There is another possibility and that is that there are problems with the
controller circuit but I think that's more unlikely. The best way to
check is to plug in a controller which works if you can borrow one and see
if it cures the problem.
'll be interested to see how you go on and what advice other listees
suggest.
I hope this helps. Best of luck
Jack Newton
Sydney Australia
89 Transporter Safari Campervan
