If I understand how the system works, the circuit samples the resistance
of the coolant. Depending on temperature, it takes a bit of time for the
sampling to take place. Once done, if the resistance is correct, the
light goes out. If not, it continues to blink. An open circuit condition
would be one in which there is no coolant between the terminals in the
sensor - like perhaps all the coolant leaked out. That would be an
infinite resistance, and the light would blink. If the coolant/water
ratio is not correct, the resistance would not be correct for the
circuit, and the light would blink. It is possible that a weak or
failing component could affect the resistance, or a ground could be
developing corrosion and thereby increase resistance and in so doing
cause the like to blink.

My $0.02

John Rodgers
88 GL Driver

Kim Springer wrote:

>So, lately I had the blinking light behind the temp needle come on randomly, but more often when cold..  No overheating, everything seems to be fine.  The coolant level looks fine to; no loss, no low level.
>
>Please explain.  Yes, I'm too lazy on Turkey day to look it up in the archives.
>
>Happy Thanksgiving everyone,
>
>Kim Springer
>2WD '89 Tristar #7 White
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