# Dual cooling fans **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** chevrolet, equinox\ **Created:** [September 15, 2024, 3:14pm UTC](https://community.cartalk.com/t/dual-cooling-fans/196246 "2024-09-15T15:14:24Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![Cavell](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/cavell/32/43396_2.png) [@Cavell](https://community.cartalk.com/u/Cavell)\ **Post date:** [September 15, 2024, 3:14pm UTC](https://community.cartalk.com/t/dual-cooling-fans/196246/1 "2024-09-15T15:14:24Z")
Locking at kids 08 equinox. The fans have always seemed to be noisy/loud when I am near it. I drove it today with ac on and noticed 1 fan was running at max and 1 was not spinning. I turned off ac and fan shutoff after 20-30 sec. I “think” both fans normally run. I had an 07 torrent to compare it too but sold it last week. I “think” torrent ran both fans normally. How does GM run dual fans usually? Does ac affect operation more than motor temp? ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [September 15, 2024, 4:53pm UTC](https://community.cartalk.com/t/dual-cooling-fans/196246/2 "2024-09-15T16:53:04Z")
Why run 2 when 1 will work? That’s what GM does. If the AC turns on one fan also turns on to draw air across the AC condenser to cool the car quicker and at low speeds before the engine heat catches up. 2 fans draw twice the power from the alternator. Why pay that price in fuel economy if you don’t have to? Most, if not all (GM or anyone else), dual fans are staged this way. So No AC, no fans until a preset temp, then one fan turns on. Reaching a higher temp and the second fan turns on. AC ON, one fan runs until a preset temp when the second on turns on. If it isn’t really hot or you are not towing the second fan rarely turns on. ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [September 15, 2024, 6:57pm UTC](https://community.cartalk.com/t/dual-cooling-fans/196246/3 "2024-09-15T18:57:25Z")
The inoperative fan motor has failed (open circuit). For low-speed operation the motors are powered in series: 6 volts per motor. For high-speed operation the motors are powered directly/parallel. Your cooling fan is always noisy because low-speed operation is inoperative, after the temperature or A/C pressure reaches a threshold, high speed engages. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [September 15, 2024, 9:46pm UTC](https://community.cartalk.com/t/dual-cooling-fans/196246/4 "2024-09-15T21:46:34Z")
Just curious, so which is it? I’ve always thought that Nevada’s theory explains how the GM 2-fan system works. Has the design changed? Edit: Looking at the schematic for the 08 nox FWD 3.4, there’s three relays that configure the fans, & there appears to be a way those relays could be set to power only one fan on hi speed. If so it appears it would be the right fan. There’s also a way to configure the relays to put both fans in hi speed mode. So the software makes the decision. My guess, both fans should in fact be on, but (presuming it is the right one that’s spinning) either the left fan is broken, or a fuse is blown. There’s three fuses involved, Fan 1 (30A), Fan 2(30A), and (just to make life interesting), EMISO 2(15 A). ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [September 15, 2024, 10:25pm UTC](https://community.cartalk.com/t/dual-cooling-fans/196246/5 "2024-09-15T22:25:40Z")
The ground circuit for the left motor is controlled by relay # 3. The relay can apply direct ground for the left motor or ground through the right-side motor, the latter powers the motors in series. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [September 15, 2024, 10:39pm UTC](https://community.cartalk.com/t/dual-cooling-fans/196246/6 "2024-09-15T22:39:48Z")
I must not be looking at the same diagram. The only path for a direct ground connection for the left motor that I can see would be when relay 2 is in the active state. I can see how both fans could be connected in series, which also involves relay 2. ---
**Author:** ![Cavell](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/cavell/32/43396_2.png) [@Cavell](https://community.cartalk.com/u/Cavell)\ **Post date:** [September 16, 2024, 1:50am UTC](https://community.cartalk.com/t/dual-cooling-fans/196246/7 "2024-09-16T01:50:53Z")
Ok. Drove my new too me torrent for 1/2 hr with ac on. Idled. Both fans were on high. Turned off ac and both fans went to low speed. Idled for about 5 min and temp went from 199-196f approx as I played with idle speed. The temp does seem to rise to 201-202 at 800rpm but dips when I raise idle to 1500. I think the fans shut off on former torrent at idle. I’ll let motor cool and start with ac off and see what fans do. ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [September 16, 2024, 5:30pm UTC](https://community.cartalk.com/t/dual-cooling-fans/196246/8 "2024-09-16T17:30:40Z")
The fans are turned on when they are needed. Multi speed fans generally operate in pairs. Try to rotate the fan blade on the inoperative motor to check if the motor is seized. ---
**Author:** ![Cavell](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/cavell/32/43396_2.png) [@Cavell](https://community.cartalk.com/u/Cavell)\ **Post date:** [September 17, 2024, 4:10pm UTC](https://community.cartalk.com/t/dual-cooling-fans/196246/9 "2024-09-17T16:10:23Z")
Drove equinox. Fans are off with ac off. Using ac runs pass side fan (10") at high speed. Driver fan (13") does not run. I idled in driveway with ac off. No fans running. Coolant temp hit 220f and no fans. I turned on ac and pass fan runs at hi speed. Temp went down to 207. Driver fan spins fine when turned by hand. Fuses are good. ---
**Author:** ![Cavell](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/cavell/32/43396_2.png) [@Cavell](https://community.cartalk.com/u/Cavell)\ **Post date:** [September 17, 2024, 5:30pm UTC](https://community.cartalk.com/t/dual-cooling-fans/196246/10 "2024-09-17T17:30:45Z")
I Powered driver fan with 12v. It spins ok. I switched relay 1 and relay 2 but left 5 pin relay 3 as is and now both fans spin at lo speed with ac on. Maybe I was expecting driver/pass fans to flip? As driver would run and pass would not? I was going to use relays from torrent as “spares”. But not needed now? Maybe reseating driver fan plug had affect? ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [September 17, 2024, 7:34pm UTC](https://community.cartalk.com/t/dual-cooling-fans/196246/11 "2024-09-17T19:34:29Z")
@Nevada_545 implies above that the fan operation is confined to three modes (my own research confirms this) 1. Both off 2. Both on, low speed 3. Both on, high speed Until you’ve confirmed number 3 is ok, there’s no way to know if the problem is resolved. ---
**Author:** ![Cavell](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/cavell/32/43396_2.png) [@Cavell](https://community.cartalk.com/u/Cavell)\ **Post date:** [September 17, 2024, 7:55pm UTC](https://community.cartalk.com/t/dual-cooling-fans/196246/12 "2024-09-17T19:55:22Z")
Idling in driveway with ac off and it hit 220 with no fans made me concerned. Turned on ac and pass fan went to hi. Driver fan was off. Temp dropped. Shutoff motor and switched relay 1and 2. Restarted with ac on and both fans were running at lo. So, something changed. Funny. Pos 1 is fan 2, yes pos 1 is fuse. And pos 2 is fan 1, yes, pos 2 is fuse ![image](https://global.discourse-cdn.com/cartalk/original/3X/4/b/4bf9efa13cf548f6b85de07792c1d42ecc81dc23.jpeg) ---
**Author:** ![jtsanders](https://avatars.discourse-cdn.com/v4/letter/j/c2a13f/32.png) [@jtsanders](https://community.cartalk.com/u/jtsanders)\ **Post date:** [September 17, 2024, 7:56pm UTC](https://community.cartalk.com/t/dual-cooling-fans/196246/13 "2024-09-17T19:56:57Z")
> [@Cavell](#): > > Maybe reseating driver fan plug had affect? Could be. I’ve had cars with electrical issues that went away after unplugging/plugging a few times. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [September 17, 2024, 9:14pm UTC](https://community.cartalk.com/t/dual-cooling-fans/196246/14 "2024-09-17T21:14:13Z")
> [@Cavell](#): > > Idling in driveway with ac off and it hit 220 with no fans made me concerned. Concern seems reasonable. I expect however 220 F is right at the high limit before the computer starts turning the fans on , with no A/C. Might be a good idea to verify the coolant temp sensor is measuring the correct resistance. Alternately, that the scan tool coolant temperature is accurate. MY understanding is the pcm reads the coolant temperature from the temp sensor, determines if AC is on or off, then from that input decides which fan mode is needed, and programs the relay controls. Do you know how to measure the control voltage applied to the relay control pin of each relay? ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [September 17, 2024, 10:34pm UTC](https://community.cartalk.com/t/dual-cooling-fans/196246/15 "2024-09-17T22:34:01Z")
> [@George\_San\_Jose1](#): > > Do you know how to measure the control voltage applied to the relay control pin of each relay? It is best to start with simple testes: check for power and ground at the motor while it is inoperative. Tapping on the motor with a hammer to see if it begins to rotate will give a clue. Now that all the connections have been disturbed, it will be more difficult to diagnose. > [@Cavell](#): > > Funny. Pos 1 is fan 2 > And pos 2 is fan 1 Those are fuses, relays are in positions 56 and 61. ---
**Author:** ![Cavell](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/cavell/32/43396_2.png) [@Cavell](https://community.cartalk.com/u/Cavell)\ **Post date:** [September 18, 2024, 2:20pm UTC](https://community.cartalk.com/t/dual-cooling-fans/196246/16 "2024-09-18T14:20:19Z")
Started cold car. 9am. Ac on. Both fans run at lo speed. Turn off ac. Both fans stop. Driver fan is bigger then pass fan. I’d say 13” vs 10” approx? And driver fan never ran previously. rectangle radiator and circular fans. 2 small fans is not using all space. and 2 large fans wont fit well. so, 1 big and 1 smaller. ![image](https://global.discourse-cdn.com/cartalk/original/3X/5/3/533537d05179187f49d9b69bbd438a5647d10ec7.jpeg) ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [September 18, 2024, 7:32pm UTC](https://community.cartalk.com/t/dual-cooling-fans/196246/17 "2024-09-18T19:32:35Z")
> [@Cavell](#): > > driver fan never ran previously. That’s not consistent w/what you said in the post above. Do you mean the driver fan has never ran at high speed ? > [@Cavell](#): > > both fans spin at lo speed with ac on ---
**Author:** ![Cavell](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/cavell/32/43396_2.png) [@Cavell](https://community.cartalk.com/u/Cavell)\ **Post date:** [September 18, 2024, 7:46pm UTC](https://community.cartalk.com/t/dual-cooling-fans/196246/18 "2024-09-18T19:46:46Z")
The driver fan never worked. Hi or lo. It is working now. Pass fan seems to be running same speed as driver fan now