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Chris (aka-Moose)
Chris (aka-Moose), Technician
Category: Chevy
Satisfied Customers: 47668
Experience:  16 years of experience
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Rebuilt and installed Ecotec 2.2 (spun #1 rod bearing).

Customer Question

Rebuilt and installed Ecotec 2.2 (spun #1 rod bearing).
Problem: Cooling fan does not come on, A/C does not work and battery does not recharge – or at least the battery light comes on nearly constant. OBD II does not show any codes.
So far:
- Verified (VF) cooling fan (CF) works
- VF continuity alternator wire to starter
- VF CF black wire ground
- VF continuity CF blue & tan wires to fuse panel
- Visually inspected for damage, burns, etc;
- Associated fuses (OK)
- Associated relays
- Engine temp sensor
- Inline diode to black & blue wires to cooling fan (was burnt)
- Replaced;
- Alternator
- Inline diode
Submitted: 1 year ago.
Category: Chevy
Expert:  Chris (aka-Moose) replied 1 year ago.

Welcome I'm Chris aka Moose

The first thing I need is the year,make,and model?

-----------About me and Just Answer------------

I am in my upper 30's, have a wife and 2 sons. I farm, fish, hunt, build, and coach youth soccer. I work on anything with an engine and have went to many schools and classes to get trained and certified. I try the best I can to share what I know and or have access to with my customers. Please consider I base my questions and answers to you, solely on the information you give me since I am not there to see, smell, hear, touch, or test. I try my best to be here everyday starting at 3pm central. Rating one of the answers, not the questions, you receive is required. Please let me know if your not pleased prior to rating so I can try to help a different way. God Bless and have a great day.

Thanks Chris

Customer: replied 1 year ago.
I will read your answer and rate accordingly. Thank you. ***** MARINES (Ret)
Customer: replied 1 year ago.
Where is your prognosis?
Customer: replied 1 year ago.
Expert:  Chris (aka-Moose) replied 1 year ago.

You may have not see what I wrote prior.

The first thing I need is the year,make,and model?

Customer: replied 1 year ago.
Sorry. 2006 Chevy Cobalt w/2.2 ecotec engine
Expert:  Chris (aka-Moose) replied 1 year ago.

Is the coolant temp getting over halfway when the fan is then needed?

While running what is the battery voltage so I can see if the alternator is charging none or some?

Customer: replied 1 year ago.
The cooling temp is near overheating and the light comes on. Max temp has been 225 before turning car off.Battery light remains on. Didn't measure any charge coming from alternator. As a last resort I removed the alternator wire from fuse block, car continued running.
Removed battery cable and left alternator cable, car stopped.
Expert:  Chris (aka-Moose) replied 1 year ago.

Since you replaced the alternator then its fine. As long as the alternator gets battery voltage on the black wire and the other 2 wires ohm test good back to the ECM, then your charging system issue is due to a faulty ECM.

On the cooling fans, you have checked the fans and they work, so that means there ground is good. The ECT is reading so its good. That leaves the relays to check. Remove both fan relays, each should have 2 pins that are powered. If so then check the signal wire from the relays to the ECM to see if they are broken doing an OHM test. If the wires are fine then its your ECM to blame.

If wire diagrams are needed, let me know.

Customer: replied 1 year ago.
It's kind of late here in DFW and I'm knee deep in another project for boy scouts so I'll attempt that tomorrow morning. I've sort of been leaning toward the ECM anyway because I had trouble-shot nearly every other part possible.If it is the ECM and I replace it, should my AC (and AC blower) work again?What is the relationship between the alternator, starter, cooling fan & AC?Was helicopter mechanic in Marines for nearly 25 years. I know they're not chevys but I don't think that I should be as stumped as I have been.Maybe we had a connector or two mis-connected when the key was initially turned following reinstalled engine??
Expert:  Chris (aka-Moose) replied 1 year ago.

The HVAC blower is not related to the other issues. i was not aware it did not work. I thought the AC did not work, which is related t hte cooling fan not working and or the ECM.

The ECM controls the fan, signal to the start, and the alternator.

Customer: replied 1 year ago.
The AC does not work, neither does the HVAC blower. The heater/defrost gets hot but doesn't blow.
Customer: replied 1 year ago.
Does the ECM have anything to do with the HVAC blower not working?
Expert:  Chris (aka-Moose) replied 1 year ago.

The ECM does not control the blower. The BCM controls the power to it and the HVAC control module and blower resistor control the ground.

Customer: replied 1 year ago.
I guess that will be my next adventure after I get this little turd running decently.
Expert:  Chris (aka-Moose) replied 1 year ago.

Have a good night.

Customer: replied 1 year ago.
Thanks. I want to check the procedures and I'll respond in the morning and let you know the status. Good night.
Expert:  Chris (aka-Moose) replied 1 year ago.