G37 Coupe

G37 Fans turn On and off?

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Old 07-20-2019 | 05:05 PM
  #16  
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So i just got done doing the continuity test on the Relay and it seems good, but when i check the voltage on the terminals I only get 12v on one 2 stay completely at 0 and the other at 00.02 i thought i was suppose to get 12v on 2 out of the 4, am I correct?
Old 07-20-2019 | 05:18 PM
  #17  
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No. Terminals 1 & 2 are power for the relay. When 12V is applied to 1 & 2, you should have continuity between terminals 3 & 5. No power, no continuity. Terminals 3 & 5 are the signal circuit for the fan module.
Old 07-20-2019 | 05:23 PM
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Yes I applied 12v to 1 & 2 and got continuity on 3 and 5, but on the Voltage test for the plug where the relay goes, i checked to see if i was getting voltage from the battery, and i only get 12v on terminal 3, 1 & 2 stay at 00.00 and terminal 5 is at 00.02, i thought i was suppose to get 12v on terminals 3 and 5 from the battery but i only get 12v on terminal 3
Old 07-20-2019 | 05:41 PM
  #19  
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Per the FSM, relay terminal values should read:
TERMINAL 1- OUTPUT 12V with IGNITION ON
TERMINAL 2- INPUT 0.7V with IGNITION ON (0 w/ IGN OFF)
TERMINAL 3- INPUT 12V direct from battery (hot at all times)
TERMINAL 5- OUTPUT 12V from terminal 3 to fan control module when relay is energized.

Seems that the power for the fan relay is directly wired to the IGNITION relay...

Last edited by ILM-NC G37S; 07-20-2019 at 05:47 PM.
Old 07-24-2020 | 09:54 PM
  #20  
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So this thread has been golden to me and very well timed!

I have this same issue, tried the factory test and no fans running. I replaced the fans with control module last year.



All was working well when I did the replacement. Both fans kicked in when AC was turned on. Winter came and then spring and then wanting to use the AC again as summer came, it wasn’t running. I toped it off with some AC coolant in a can and I think put too much pressure in the AC system. I thought this because the AC fans no longer ran, and the car temp would rise when stationary – not good!



I thought I’d get the AC properly evacuated and re-gassed at the local shop which they did, but told me still warm air. They did some more work (flushed the AC system and re-gassed) and told me some cool air!



So now I presume I have the correct mass of refrigerant with the correct pressure in the AC system.



Still no fans!



I ran the test – no fans at all. Nada.



I tested the rely – works well, even swapped it for the neighbouring relay. Nothing.



I tested the power to the rely terminals I got:



TERMINAL 1- OUTPUT 0.7V with IGNITION ON
TERMINAL 2- INPUT 12V with IGNITION ON (0 w/ IGN OFF)
TERMINAL 3- INPUT 0V direct from battery (hot at all times)
TERMINAL 5- OUTPUT 0V from terminal 3 to fan control module when relay is energized.




Below is what I should have got!

TERMINAL 1- OUTPUT 12V with IGNITION ON
TERMINAL 2- INPUT 0.7V with IGNITION ON (0 w/ IGN OFF)
TERMINAL 3- INPUT 12V direct from battery (hot at all times)
TERMINAL 5- OUTPUT 12V from terminal 3 to fan control module when relay is energized.




So now I’m stumped.



It seems like I don’t have power at the correct terminals of the rely (I will double check in the morning).



I am thinking of trying to get a new fan control module to see if that will resolve the issue, but seeing I don’t seem to have the right power at the rely, I think it wont.



Is there a fuse that services the PWM relay? I found a 50amp one for the cooling fan under the hood – it was ok.



Any help greatly appreciated!






Old 07-25-2020 | 11:38 AM
  #21  
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Let's see... first, it is relay, not "rely"...

You should have 12V at all times on relay terminal #3. If you do not have power, then you have to look for a blown fuse or a bad wire connection. The relay feeds the fan module control circuit off of a 50amp FUSIBLE LINK (NOT a standard fuse). The relay gets energized from the IPDM/er.

I would recommend:
1) double check that fusible link;
2) make sure the relay is actually energizing;
3) check the wires for any damage- especially terminal #3;

For a TEMPORARY, quick test, I would run a jumper wire from the battery to terminal #3 then run the IPDM/er self test to see if the fans come on. If they do, then your problem lies upstream (relay, wiring, fusible links etc.).

Do not start throwing parts at the problem until you know what it wrong.

Last edited by ILM-NC G37S; 07-25-2020 at 11:58 AM.
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Old 07-27-2020 | 09:07 PM
  #22  
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Thanks so kindly for your quick reply to my relay issue!

I couldn't get power to at the relay.

I booked it into go to the shop as I'd about exceeded my electrical capabilities and time to throw at this issue. The relay housing is a PIA to work around as it's so close to the inner wing.

I'd also ordered a new fan control unit. that arrived tonight - It was $100. I plugged it an and ran the test sequence - cool air blowing from my fans! Yes! A little disappointing as the last controller is less than a year old. I will try and claim a warranty!

Cool driving everyone!
Old 07-27-2020 | 09:26 PM
  #23  
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Hmmm... that's odd. But, the good news is that you are up and running. Hopefully your warranty claim will be successful.

Thanks for the update...
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