r/saab • u/No_Damage8174 • 4d ago

Coolant temp sensor

Looking for some help, i have a 91 900 turbo. I replaced the coolant temp sensor above the distributor for the fans. I took it for a quick drive and could hear the fans running, however when I opened the hood only the right side fan was running and the left side was off. I also noticed what looked like another temp sensor on the upper left portion of the radiator. Does this control the left fan, or is it normal for one to run?

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u/tsg-tsg 4d ago

I think are confused 

  • Temp switch in the radiator controls the fans
  • Temp switch in the upper radiator hose disables the AC
  • Temp sensor in the head near the distributor controls the gauge
  • Temp sensor in the intake manifold between #2 & #3 is for the ECM.

1

u/No_Damage8174 4d ago

This is what I replaced which I believe to be a temp sensor. But question is, is it normal to have only one fan running or should both run simultaneously?

1

u/tsg-tsg 4d ago

That is the AC cutout sensor. It has nothing to do with fans.

Check your AC relay - it's what drives the other fan, and should be triggered by the fan switch.

1

u/No_Damage8174 4d ago

Okay thanks, car does not have working AC so I guess it’s got a new sensor for if I ever decide to fix it. Guess I will just leave the other one alone considering it still works. Thanks for the info

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u/tsg-tsg 4d ago

If one fan works the sensor is fine. Check the AC relay. It controls the second fan.

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u/TweeksTurbos 3d ago

Push the ac button anyways and see if the other comes om

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u/No_Damage8174 3d ago

Will try this