Cooling fan not on
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From: Niagara Falls
Cooling fan not on
2003 Quicksilver Coupe M6 50,000km Garage Queen bone stock, even the original wiper blades 
Pulled it out today , let it come to full temp and noticed the temp was hotter than usual. Did not hear fans on as usual. Checked fuses, all good, relays seem to be good. Applied voltage to relays and all had closed circuit as it should. Used my mini amp charge to provide 12v for test. Never had this problem before. In addition checking the fuses notice that there is a fuse for Coolfan 2 but no relay #43 for Coolfan2 per the fusebox layout..(probably GM short cut) and it appears that there are only two fans for this car.. Both fans spin freely by hand.
Regardless , everything was working last fall. What and where can I check next. Thx
Pulled it out today , let it come to full temp and noticed the temp was hotter than usual. Did not hear fans on as usual. Checked fuses, all good, relays seem to be good. Applied voltage to relays and all had closed circuit as it should. Used my mini amp charge to provide 12v for test. Never had this problem before. In addition checking the fuses notice that there is a fuse for Coolfan 2 but no relay #43 for Coolfan2 per the fusebox layout..(probably GM short cut) and it appears that there are only two fans for this car.. Both fans spin freely by hand.
Regardless , everything was working last fall. What and where can I check next. Thx
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From: Cape Coral, Florida
2003 Quicksilver Coupe M6 50,000km Garage Queen bone stock, even the original wiper blades
Pulled it out today , let it come to full temp and noticed the temp was hotter than usual. Did not hear fans on as usual. Checked fuses, all good, relays seem to be good. Applied voltage to relays and all had closed circuit as it should. Used my mini amp charge to provide 12v for test. Never had this problem before. In addition checking the fuses notice that there is a fuse for Coolfan 2 but no relay #43 for Coolfan2 per the fusebox layout..(probably GM short cut) and it appears that there are only two fans for this car.. Both fans spin freely by hand.
Regardless , everything was working last fall. What and where can I check next. Thx
Pulled it out today , let it come to full temp and noticed the temp was hotter than usual. Did not hear fans on as usual. Checked fuses, all good, relays seem to be good. Applied voltage to relays and all had closed circuit as it should. Used my mini amp charge to provide 12v for test. Never had this problem before. In addition checking the fuses notice that there is a fuse for Coolfan 2 but no relay #43 for Coolfan2 per the fusebox layout..(probably GM short cut) and it appears that there are only two fans for this car.. Both fans spin freely by hand.
Regardless , everything was working last fall. What and where can I check next. Thx
Don’t know what you mean by “applied voltage to relays and had closed circuit”...closed circuit ??......never heard of that before !!... all relays have 2 power sources...a load and control...if you jump pins 87 and 30 (load side) do the fans operate !!!
Last edited by C5 Diag; Apr 28, 2021 at 05:50 PM.
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Joined: Oct 2005
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From: Niagara Falls
Must be a sensor for temp to turn on fans, if that is faulty would it still make the fans turn on by jumping 87-30?
When I tested the relay I removed it from the car. Connected my 12v 1amp power supply to terminals 85 and 86. Checked 87 , 30 terminals for continuity, and I got it , when I removed power supply did not get continuity, so the relay(s) appear to be functioning properly..
When I tested the relay I removed it from the car. Connected my 12v 1amp power supply to terminals 85 and 86. Checked 87 , 30 terminals for continuity, and I got it , when I removed power supply did not get continuity, so the relay(s) appear to be functioning properly..
Last edited by flexvette; Apr 28, 2021 at 08:16 PM.
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From: Cape Coral, Florida
Last edited by C5 Diag; Apr 28, 2021 at 08:33 PM.
Moderator, Tech Contributor
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From: Cape Coral, Florida
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,615
Likes: 4,062
From: Cape Coral, Florida
Last edited by C5 Diag; Apr 28, 2021 at 08:20 PM.
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From: Cape Coral, Florida
The relay pin numbers are on the bottom of the relay...if you have a 12 volt test light make sure pin 87 is powered...just turn the key on...to check ground connect test light to battery positive to check pin 30...when probing pin 30 test light should light if ground is good..I use an old headlight bulb...if fan draws 4 amps for instance I use a headlight that draws 4 amps !!
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From: Niagara Falls
Tried again to jump.... you where correct... I must have had the jumper crossed or the wire end not long enough to touch.. anyway it worked.. thanks for that.
Relay 43 , by sound, seems to turn on both fans.. Relay 45 , by sound , seems to turn on one fan. Both of those relays have a 30A fuse associated with them.. Relay 44 for Coolingfan 3 has no corresponding fuse ( empty) and I could not get anything from this one when I jumped it... and your pic with the white circle is correct as well my two mistakes..
So both fans work as they should.. so another member mentioned a Sensor, so I went on YT to see if anyone has a test method , no joy,, but there is a vid of how to replace it, so at least I know where it is. Any suggestions on how to test this sensor.. without taking it out.. apparently it is hidden underneath the alternator,, so not easily serviceable from the sensor ,, there must be a connection somewhere to test from...
Relay 43 , by sound, seems to turn on both fans.. Relay 45 , by sound , seems to turn on one fan. Both of those relays have a 30A fuse associated with them.. Relay 44 for Coolingfan 3 has no corresponding fuse ( empty) and I could not get anything from this one when I jumped it... and your pic with the white circle is correct as well my two mistakes..
So both fans work as they should.. so another member mentioned a Sensor, so I went on YT to see if anyone has a test method , no joy,, but there is a vid of how to replace it, so at least I know where it is. Any suggestions on how to test this sensor.. without taking it out.. apparently it is hidden underneath the alternator,, so not easily serviceable from the sensor ,, there must be a connection somewhere to test from...
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Joined: Sep 2013
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From: Cape Coral, Florida
Tried again to jump.... you where correct... I must have had the jumper crossed or the wire end not long enough to touch.. anyway it worked.. thanks for that.
Relay 43 , by sound, seems to turn on both fans.. Relay 45 , by sound , seems to turn on one fan. Both of those relays have a 30A fuse associated with them.. Relay 44 for Coolingfan 3 has no corresponding fuse ( empty) and I could not get anything from this one when I jumped it... and your pic with the white circle is correct as well my two mistakes..
So both fans work as they should.. so another member mentioned a Sensor, so I went on YT to see if anyone has a test method , no joy,, but there is a vid of how to replace it, so at least I know where it is. Any suggestions on how to test this sensor.. without taking it out.. apparently it is hidden underneath the alternator,, so not easily serviceable from the sensor ,, there must be a connection somewhere to test from...
Relay 43 , by sound, seems to turn on both fans.. Relay 45 , by sound , seems to turn on one fan. Both of those relays have a 30A fuse associated with them.. Relay 44 for Coolingfan 3 has no corresponding fuse ( empty) and I could not get anything from this one when I jumped it... and your pic with the white circle is correct as well my two mistakes..
So both fans work as they should.. so another member mentioned a Sensor, so I went on YT to see if anyone has a test method , no joy,, but there is a vid of how to replace it, so at least I know where it is. Any suggestions on how to test this sensor.. without taking it out.. apparently it is hidden underneath the alternator,, so not easily serviceable from the sensor ,, there must be a connection somewhere to test from...
Just remove the connector and get your ohmeter out if you have a DVOM and put the leads across the 2 terminals of the sensor..see what resistance you have and compare it to this chart...let the car sit overnight..use the outside air temp for the chart...what does the temp compare to your DIC coolant temp or the gauge after the car sits overnight...should be close. As far as wiring you should see 5 volts on the yellow wire key ON...the ground is at the PCM...to check that connect a 12 volt test light to battery positive...when you touch it to the brown wire the test light will light signifying a good ground...if you do read 5 volts on the yellow wire connect the black lead of the voltmeter to that brown wire...should should see 5 volts doing it that way !!
l
Last edited by C5 Diag; Apr 29, 2021 at 12:44 PM.
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Joined: Sep 2013
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From: Cape Coral, Florida
Tried again to jump.... you where correct... I must have had the jumper crossed or the wire end not long enough to touch.. anyway it worked.. thanks for that.
Relay 43 , by sound, seems to turn on both fans.. Relay 45 , by sound , seems to turn on one fan. Both of those relays have a 30A fuse associated with them.. Relay 44 for Coolingfan 3 has no corresponding fuse ( empty) and I could not get anything from this one when I jumped it... and your pic with the white circle is correct as well my two mistakes..
So both fans work as they should.. so another member mentioned a Sensor, so I went on YT to see if anyone has a test method , no joy,, but there is a vid of how to replace it, so at least I know where it is. Any suggestions on how to test this sensor.. without taking it out.. apparently it is hidden underneath the alternator,, so not easily serviceable from the sensor ,, there must be a connection somewhere to test from...
Relay 43 , by sound, seems to turn on both fans.. Relay 45 , by sound , seems to turn on one fan. Both of those relays have a 30A fuse associated with them.. Relay 44 for Coolingfan 3 has no corresponding fuse ( empty) and I could not get anything from this one when I jumped it... and your pic with the white circle is correct as well my two mistakes..
So both fans work as they should.. so another member mentioned a Sensor, so I went on YT to see if anyone has a test method , no joy,, but there is a vid of how to replace it, so at least I know where it is. Any suggestions on how to test this sensor.. without taking it out.. apparently it is hidden underneath the alternator,, so not easily serviceable from the sensor ,, there must be a connection somewhere to test from...
Last edited by C5 Diag; Apr 29, 2021 at 03:20 PM.
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Joined: Oct 2005
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From: Niagara Falls
Canadian export car. CF3 Relay 44 is there but no fuse for it, and diagram shows Relay but shows fuse slot empty.. so no power to it ? Correction, checked again and I do have fuse 14, 10A so relay 44 is powered by a smaller fuse than the other two.
Looked at the temp sensor , was able to get the connector off but can't get at the sensor to check the ohms of it.. Will need to remove the alternator,. not the end of the world but a pain for sure. Will have to do it.
Looking at the wiring diag. I see that the relays are for low speed and high speed, hence the different sounds I notice.. good info
Did not think about the DIC. It cold today, 46deg. difficult to work in unheated garage. If the DIC takes its signal directly from the temp sensor and it gives me a reading similar to the current temp with the car cold, would that mean that the temp sensor is functioning properly??? maybe too simplistic??
Looked at the temp sensor , was able to get the connector off but can't get at the sensor to check the ohms of it.. Will need to remove the alternator,. not the end of the world but a pain for sure. Will have to do it.
Looking at the wiring diag. I see that the relays are for low speed and high speed, hence the different sounds I notice.. good info
Did not think about the DIC. It cold today, 46deg. difficult to work in unheated garage. If the DIC takes its signal directly from the temp sensor and it gives me a reading similar to the current temp with the car cold, would that mean that the temp sensor is functioning properly??? maybe too simplistic??
Last edited by flexvette; Apr 29, 2021 at 04:01 PM.
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Joined: Sep 2013
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From: Cape Coral, Florida
Canadian export car. CF3 Relay 44 is there but no fuse for it, and diagram shows Relay but shows fuse slot empty.. so no power to it ? Correction, checked again and I do have fuse 14, 10A so relay 44 is powered by a smaller fuse than the other two.
Looked at the temp sensor , was able to get the connector off but can't get at the sensor to check the ohms of it.. Will need to remove the alternator,. not the end of the world but a pain for sure. Will have to do it.
Looking at the wiring diag. I see that the relays are for low speed and high speed, hence the different sounds I notice.. good info
Looked at the temp sensor , was able to get the connector off but can't get at the sensor to check the ohms of it.. Will need to remove the alternator,. not the end of the world but a pain for sure. Will have to do it.
Looking at the wiring diag. I see that the relays are for low speed and high speed, hence the different sounds I notice.. good info
Fuse 14 is a 10 AMP !!!...other 2 are 10. Like I said you should have 3 relays and fuses !!...with 12 volt test light see if you have power at 2 pins of relay 43 and 45...key on...relay 44 should only have power on 1 pin...I don’t know if you are experienced in reading a wiring diagram ??
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From: Niagara Falls
If I stare at them will figure it out eventually 
Just went through the DIC . Coolant temp 57F , thermometer in the garage says 56F so that's good. So the temp sensor must be working properly????
No other codes that are current, some H codes.
Raining out today so I will have to run the car tomorrow to full temp and see if any changes. If it still doesn't work will have to remove alternator and check sensor and can change relays , they are cheap. I would imagine relays may work under test conditions and fail under full load???
Will look for G102 as well and see but since fans are working not likely that and I don't drive it in winter reduced chance of corrosion.
Just went through the DIC . Coolant temp 57F , thermometer in the garage says 56F so that's good. So the temp sensor must be working properly????
No other codes that are current, some H codes.
Raining out today so I will have to run the car tomorrow to full temp and see if any changes. If it still doesn't work will have to remove alternator and check sensor and can change relays , they are cheap. I would imagine relays may work under test conditions and fail under full load???
Will look for G102 as well and see but since fans are working not likely that and I don't drive it in winter reduced chance of corrosion.
Last edited by flexvette; Apr 29, 2021 at 05:02 PM.
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From: Niagara Falls
Got car out today, brought up to full temp. yeah,, fans came on.... 223f and off at 216f approx.. so it is working now. ??? who knows ... I guess this kind of thing happens to garage queens, gets stagnant when not used... I will have to keep an eye on the temp so I will leave that setting up on DIC for now and see what happens to the temp..
Suspicious of the relays, several yrs ago had to remove the passengers side door control module, autolocks not working , removed 2 relays and replaced, and reinstalled and has worked since. I was able to do that with the help of CF members, otherwise it would have cost me $400 for a new board, instead cost about $10.
Thank you Members for your help.
Suspicious of the relays, several yrs ago had to remove the passengers side door control module, autolocks not working , removed 2 relays and replaced, and reinstalled and has worked since. I was able to do that with the help of CF members, otherwise it would have cost me $400 for a new board, instead cost about $10.
Thank you Members for your help.
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From: Cape Coral, Florida
I would just go and replace all the relays with OEM...these relays are about $20.00 a pop at a dealership...I had a bad fuel pump relay last summer and just got one from the local dealership !!