99 Sunfire 2.2L overheating

Tiny
JETSTREAM
  • MEMBER
  • 1999 PONTIAC SUNFIRE
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?
Saturday, September 1st, 2007 AT 11:37 AM

2 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 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.
Was this
answer
helpful?
Yes
No
Sunday, December 9th, 2018 AT 8:40 AM
Tiny
JETSTREAM
  • MEMBER
  • 6 POSTS
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).
Was this
answer
helpful?
Yes
No
Sunday, December 9th, 2018 AT 8:40 AM

Please login or register to post a reply.

Sponsored links