1999 Mazda 626 Cooling and aircondition fans

Tiny
CALL2PREACH
  • MEMBER
  • 1999 MAZDA 626
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 121,000 MILES
I recently took my car to a machanic to check the cooling fan and aircondition fan to see why they were not working and the car was overheating. He called me and informed me that he had check fan by by-passing the relays and the fan were operational. He concluded that it must be a computer problem or grounding problem but he could not locate the exact cause. I had the transmission rebuilt on the car about a mouth ago. He explain to me that it may be a gorund that runs to the transmission block. My questions is, what can be causing the the fans no to be properly grounded or could their be a computer problem, which I wasn't aware of any thpe computer boards in my car. Nelp fast!

Thank You
Wednesday, April 29th, 2009 AT 9:53 AM

7 Replies

Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Hi call2preach,

Thank you for the donation.

The cooling fan relays are controlled by the Power Control Module ( computer).
Is the Check Engine Light showing? If you are able to retrieve the code, it would allow us to go into diagnostics to verify the source.

Here are the cooling fan circuit.


https://www.2carpros.com/forum/automotive_pictures/192750_CoolingFan99Mazda626a1_1.jpg



https://www.2carpros.com/forum/automotive_pictures/192750_CoolingFan99Mazda626a2_1.jpg

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Thursday, April 30th, 2009 AT 11:13 AM
Tiny
CALL2PREACH
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No, the check engine light is not on. The only indicator warining I am getting is the thermostat guage is going to 'H' (HOT) when I am idle. What code are you refering to that I can retrieve that would allow you to go into diagnostics to verify the source.
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Thursday, April 30th, 2009 AT 1:09 PM
Tiny
KHLOW2008
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What I am refering to is Dignostic Trouble Codes.

Though the CEL might not be showing, there might be some codes stored in PCM. I would suggest getting a scan done to retrieve for codes.

Codes linked to this problem would most likely be P1460, P1464, P1474, P1479.

Does the A/C compressor work when engine is not overheating?
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Thursday, April 30th, 2009 AT 8:59 PM
Tiny
CALL2PREACH
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Yes the A/C compressor is working.
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Friday, May 1st, 2009 AT 9:27 AM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
When A/C is working, the fans do not come on at any time?
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-1
Saturday, May 2nd, 2009 AT 8:14 AM
Tiny
CALL2PREACH
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No not at all
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Monday, May 4th, 2009 AT 2:57 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
At PCM connector terminals # 17 ( Gray Wire) and # 45, use test lamp to ground them and check if fans comes on. If yes, the PCM is faulty. If fans does not come on, remove fan relays and with ignition switch ON, there should be 2 terminals with battery voltage.
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Tuesday, May 5th, 2009 AT 11:12 AM

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