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Dan, Technician
Category: Pontiac
Satisfied Customers: 24206
Experience:  Independent Shop Experience, 2 Year Automotive Diploma, & Access to Information Database
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2001 grand prix 3.1 radiator fans only work on low speed.

Customer Question

2001 grand prix 3.1 radiator fans only work on low speed. They do work on high when the a/c is on. All 3 fan relays (main, cooling fan 1, cooling fan 2) and temperature sensor have been changed.
Submitted: 10 months ago.
Category: Pontiac
Expert:  Dan replied 10 months ago.

Hello, my name is ***** ***** I'm here to help get your problem solved.

Expert:  Dan replied 10 months ago.

Why do you say high speed isn't working? Is vehicle overheating?

Customer: replied 10 months ago.
Engine temperature climbs above 215 up to 235 in stop and go traffic. I have checked to see if the fans are on when this happens and they are always at low speed. The fans work on high speed only when A/C is on.
Expert:  Dan replied 10 months ago.

High speed isn't supposed to turn on until 230, are you monitoring temp with scan tool?

Customer: replied 10 months ago.
No, just what the temperature gage in the car. I have also changed the engine temperature sensor.
Customer: replied 10 months ago.
this engine has never gone above 215 in the 16yrs I have owned it.
Expert:  Dan replied 10 months ago.

I agree, it shouldn't even need high speed fan. Since it is getting so hot it sounds like your radiator is getting clogged. I'd personally start by replacing thermostat and if that doesn't help replace radiator. As far as cooling fan issue, I would connect a scantool to make sure actual temp is reaching at least 230 which can be done at oriely auto parts for free, if not then everything is fine and gauge just isn't that accurate. If it is going over 230 but high speed is not coming on that would mean the PCM has failed. Since high speed works with AC on that proves wiring is good. Let me know if you have more questions, thanks.