my radiator fan won't shut off

FoBoT

No Lifer
Apr 30, 2001
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what part needs to be replaced? i have the book so if it isn't buried inside the engine i can hopefully handle it

i pulled the fuse for it so it doesn't run the battery down, but now i don't drive it on hot days for fear of it overheating if i get stuck in traffic

thanks
 

nweaver

Diamond Member
Jan 21, 2001
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a lot of cars will continue to run after you shut down for a short period of time. This is normal. If it never shuts off, it's likely a thermal switch connected to the fan that shuts it off after a period of time. It's hooked to the fan and plugs into the radiator usually.
 

FoBoT

No Lifer
Apr 30, 2001
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Originally posted by: nweaver
a lot of cars will continue to run after you shut down for a short period of time. This is normal. If it never shuts off, it's likely a thermal switch connected to the fan that shuts it off after a period of time. It's hooked to the fan and plugs into the radiator usually.

no, this is never
i had the fuse pulled for a year, and last night i put it back. the car hasn't run in a week. the fan started running

thanks. i'll look in the book for the 'thermal switch'
 

Vette73

Lifer
Jul 5, 2000
21,503
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Probable have a bad Rad. fan switch. If it goes bad it can fault to ground state and keep running the fan. With the key in the on position, the fan should be on, disconect the rad. fan switch. If the fan stops then replace the rad. fan switch. If the fan keeps running check/replace the rad. fan relay.
 

91TTZ

Lifer
Jan 31, 2005
14,374
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Check to see how your sensors are set up. I had a Saturn that had 2 coolant temperature sensors. The first one sent a signal to the gauge in the car, and the second one sent the signal to the ECU. The second one went bad, so even though the gauge indicated a normal temperature my fan stayed on all the time.
 

boomerang

Lifer
Jun 19, 2000
18,883
641
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I vote for relay too.

If all the relays are grouped together in a box under the hood, you could do a temporary swap to verify the fan relay is the culprit. They wouldn't have to grouped together to do it but it would make it really easy.