Robert Smythe wrote:

> My coolant light flashes at startup, then goes out, temp guage never goes
> past half. Am I fooling myself in my speculation that its just testing
> the
> function of the circuit with this behavior?
>
> Robert
> 90 MV
>
>
You are correct.

The specs call for a coolant mixture of 50/50 coolant to water. That
mixture gives a specific resistance between the two electrodes on the
coolant level sensor. Evidently on startup the circuit assumes an open
circuit or infinity resistance until the correct voltage for the circuit
is read,  at which time the light goes out. If the mixture is incorrect,
or the tank is low on coolant and the electrodes exposed, the resistance
is incorrect, the voltage reading is wrong and the light will come on.
Important to keep that coolant mixture at 50/50, as well as keeping the
tank full.

Regards,

John Rodgers
88 GL Driver