Hi David J and Lynne J Shepherd:
>
>Thank you for your posting.
>
>I took the car to Expert Tire (Firestone) this morning (they're the
>only service shop open in our town on Sundays) and advised their
>service technician of the procedures I performed on the vehicle. >
>He measured the voltage on ECM connection C10 with the vehicle in Run
>mode (that is, the ignition key was turned on) and there was NO
>voltage there. Therefore there is no voltage getting to the collant
>temperature sensor from the ECM.
>
>Yesterday (I forgot to put this on my original posting), I measured
>the voltage at connection B of the collant fan pressure switch and
>there was NO voltage there also. Therefore there is no voltage
>getting to the collant fan pressure switch from the ECM.
>
>It looks like the ECM is failing to send voltages to the two sensors
>so that they can communitate with the ECM.
>
>> "If these inputs are reaching the ecm it is possible the problem is in the
>> ecm, such as a quad driver bad...."
>
>What is a "quad driver?"
>
>The service technition suggested that I jumper the collant fan relay
>so that the collant (radiator) fan is alway on when the car is
>running. This way the car won't overheat. If the ECM is bad, his
>suggestion will bypass these sensors and allow me to drive the car
>without worring about it overheating.
>
>Is there a downside to this suggestion...such as perhaps overheating
>of the collant (radiator) fan by having it running all the time? >
I doubt it will overheat as I'm sure that in the summer there are times when it runs practically all the time anyway. It might wear out sooner but a new fan motor is probably only 50 bucks and would last another 50K miles most likely. I'd probably hook up an aftermarket thermostat kit to it so it only runs when the radiator temp goes over
190. I'd also hook it to the AC so it always runs if the AC is on. If you do that, hook it thru a relay, not direct, so you don't mess up anything else on the circuit by creating too much load.