99 Sunfire 2.2L overheating

1999 PONTIAC SUNFIRE
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JETSTREAM
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  • 6 POSTS
I have a 99 Sunfire 2.2L no A/C, Auto and 105,000Km.

The cooling fan is not turning on at all. The fuse, the relay, the coolant temp sensor, and the fan itself have been checked and work perfectly. I have also checked the circuits for the coolant temp sensor and the fan and they to check out okay.

However when I unplug the coolant temp sensor (with the engine running) the cooling fan comes on right away. My guess is the PCM.
Anyone have any other ideas?
Sep 1, 2007 at 11:37 AM
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RASMATAZ
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  • 75,992 POSTS
The PCM commands the cooling fan by grounding the relays. Its a lot cheaper just to hot wire the fan motor than to replace the PCM by using its power source and ground.

Good luck.
Dec 9, 2018 at 8:40 AM
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JETSTREAM
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Thank you for your quick response!

I take it from your reply, that the PCM is the problem then. Thanks for the tip on hot wiring the fan but I have sourced a PCM from a wrecker for very cheap ($60.00 and tested).
Dec 9, 2018 at 8:40 AM