Re: Is this consistent with a failing coolant temperature sensor?

jim wrote:
>
> Matt wrote:
>
>>> The computer will never go closed loop running that cold...
>> I don't know which loop you mean. Explain?
>>
>
> The computer relies on the info from the coolant temperature sensor. That is
> different from the sending unit for the dash gauge.


That is surprising---not that I would know.

In the intake manifold I found two devices other than the injectors.
One is toward the rear of the car, (on the side with the even-numbered
bank of cylinders). When I unplug it, the gauge stops working. The
other is on the end of the manifold beneath the throttle body. When I
unplug that one, the gauge is unaffected. Your post seems to imply that
that one gives input to the computer. Which one controls the warning light?

I'm thinking that if one sending unit is bad, maybe the other is too.
Mileage is 160K.

Maybe I should get somebody to hook the car to a computer for general
diagnostics. Presumably a bad temperature-sending unit would be
detectable. Should I go to the GM dealer for the diagnostic---or would
a large repair shop have the right equipment?