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Both Cooling fans not coming on

Old 01-25-2014, 02:51 PM
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Both Cooling fans not coming on

1989 GTA.. As stated above, both fans are not turning on. I located what appears to be 2 relays on the passenger side..one on the side of the Radiator, and the other laying down and tucked along side the Canister. ALso not sure if it is related but the A/C stopped working around the same time I noticed the fans where no longer working...any ideas before I go out and buy 2 relays for this thing??? could it be something else?? Thanks!
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Old 01-26-2014, 05:45 PM
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Re: Both Cooling fans not coming on

One relay/fan is controlled by the switch in the passenger head. Try grounding the wire, should activate the relay and fan. The other is computer controller. I don't remember off hand how to force it to turn on.
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Old 01-28-2014, 10:57 AM
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Re: Both Cooling fans not coming on

Turn on the AC, that will activate both fans. If they work, then half your work is done.
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Old 01-28-2014, 06:55 PM
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Re: Both Cooling fans not coming on

Originally Posted by MoJoe View Post
One relay/fan is controlled by the switch in the passenger head. Try grounding the wire, should activate the relay and fan. The other is computer controller. I don't remember off hand how to force it to turn on.

Thanks MoJoe, I know about the switch on the passenger head, but I'm just wondering if there is supposed to be two relays for the fan, both on the passenger side..I found the one relay on the radiator shroud, then I discovered the other one tucked behind the Canister??? I Always only read about the one relay on the shroud. Just wondering if this is normal??

Last edited by 87Iroc5.0; 01-28-2014 at 06:59 PM.
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Old 01-28-2014, 06:57 PM
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Re: Both Cooling fans not coming on

Originally Posted by Ozz1967 View Post
Turn on the AC, that will activate both fans. If they work, then half your work is done.
Thanks Ozz, But that's just it...the A/C no longer turns on! It went out around the same time I noticed the fans where not working..I am wondering if these two problems are related??
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Old 01-28-2014, 09:46 PM
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Re: Both Cooling fans not coming on

Originally Posted by 87Iroc5.0 View Post
but I'm just wondering if there is supposed to be two relays for the fan, both on the passenger side..I found the one relay on the radiator shroud, then I discovered the other one tucked behind the Canister??? I Always only read about the one relay on the shroud.
I'm a Chevy guy, and you Pontiac guys do some things backwards! My Google-fu was decent tonight. This seems like what you are looking at.

The factory dual fan has one relay per fan. Two fans = two relays. On the Camaro, both are between the battery and radiator, mounted on the rad support, on the passenger side. A relay on the driver's side is likely a high beam cutout for fog lamps.

Even though location may be reversed on your GTA, there should be a primary cooling fan relay. Then, the heavy duty, dual fan/relay piggy-backs through a plug near the first relay.
This shows the fan relays, lower right. Unfortunately, does not show where the plugs are, like the factory service manual. Follow the large orange wire (fuseable link from battery), and it should lead you to both relays.

With a multi-meter or test light, check the big orange wire for power... make sure the fuseable link didn't blow.
Also, there is a 20A fuse powering the relays... Make sure that isn't blown either. I assume the fuse is "hot in run", so you will have to turn the key on to see 12v on the relay signal wire(s).

Last edited by MoJoe; 01-28-2014 at 09:49 PM.
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Old 01-29-2014, 09:35 AM
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Re: Both Cooling fans not coming on

Originally Posted by MoJoe View Post
I'm a Chevy guy, and you Pontiac guys do some things backwards! My Google-fu was decent tonight. This seems like what you are looking at.

The factory dual fan has one relay per fan. Two fans = two relays. On the Camaro, both are between the battery and radiator, mounted on the rad support, on the passenger side. A relay on the driver's side is likely a high beam cutout for fog lamps.

Even though location may be reversed on your GTA, there should be a primary cooling fan relay. Then, the heavy duty, dual fan/relay piggy-backs through a plug near the first relay.
This shows the fan relays, lower right. Unfortunately, does not show where the plugs are, like the factory service manual. Follow the large orange wire (fuseable link from battery), and it should lead you to both relays.

With a multi-meter or test light, check the big orange wire for power... make sure the fuseable link didn't blow.
Also, there is a 20A fuse powering the relays... Make sure that isn't blown either. I assume the fuse is "hot in run", so you will have to turn the key on to see 12v on the relay signal wire(s).

Thanks MoJoe!!! This was a HUGE help!!!
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Old 03-05-2014, 06:28 PM
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Re: Both Cooling fans not coming on

Hi - I have a 1988 5.7 IROC with AC - just to confirm, are my fan relays also between the battery and the radiator? My secondary fan DOES NOT come on when the car gets hot and Im trying to determine the problem - Also, could the temp sender near the #8 spark plug also cause this? - thanks

Last edited by BBOWWLER; 03-05-2014 at 06:32 PM. Reason: multi quote
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Old 03-05-2014, 06:42 PM
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Re: Both Cooling fans not coming on

One fan is controlled by a temp switch in the passenger side head. The other is computer controlled. I don't recall off hand the parameters were the computer turns on the fan.
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Old 03-05-2014, 07:48 PM
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Re: Both Cooling fans not coming on

https://www.thirdgen.org/forums/cool...-diagrams.html

You will be able to figure out which relay is which by the color coding in the page above. It's good advice for figuring out how and when the fans are supposed to come on.
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Old 03-07-2014, 05:43 PM
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Re: Both Cooling fans not coming on

On my 84 T/A, my Fan relay is located on the firewall near the brake booster.
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Old 07-11-2019, 08:02 AM
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Re: Both Cooling fans not coming on

Originally Posted by MoJoe View Post
One relay/fan is controlled by the switch in the passenger head. Try grounding the wire, should activate the relay and fan. The other is computer controller. I don't remember off hand how to force it to turn on.
I changed that one. The switch on the head. Changed it to a 205 instead of the stock one. Still didnít work
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Old 07-12-2019, 01:44 PM
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Re: Both Cooling fans not coming on

Originally Posted by Klleino12 View Post
I changed that one. The switch on the head. Changed it to a 205 instead of the stock one. Still didn’t work
Did you try grounding the wire going to that fan switch with the key on as described? That would show if the wiring, relay and fan are good.
Do that
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Old 07-12-2019, 07:45 PM
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Re: Both Cooling fans not coming on

Originally Posted by Klleino12 View Post
I changed that one. The switch on the head. Changed it to a 205 instead of the stock one. Still didnít work
Did you put any tape or thread sealer on the switch? If so, this would cause it to not ground properly, if that's the case. If not it could be a bad switch.
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Old 07-12-2019, 08:48 PM
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Re: Both Cooling fans not coming on

Originally Posted by MoJoe View Post
The other is computer controlled. I don't recall off hand the parameters were the computer turns on the fan.
(I'm fully aware this is a resurrected post)
Does the fan come on if you try to retrieve trouble codes ? (It should)

https://www.obd-codes.com/faq/read-g...codes-free.php
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