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Cooling Fan on High


DPS.01

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Trying to figure this one out. 
with the vehicle idling for a while, the high speed fan will turn on as it should, however it does not cycle off. 
 

ED04 show 72 degrees…also not sure why OXY is highlighted….

I have lots to learn about use of the on board diagnostic system on these cars. 
 

When the car is turned off, the high speed fan turns off.  If vehicle is restarted, the fan stays off until the coolant temp rises. 

 

CA023571-5CDF-4098-AAC5-C787338ABA22.thumb.jpeg.89c54da691b03608e53be6f372d56b21.jpeg

Edited by DPS.01
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Well that is open loop. OXY on steady just means the O2 is not cycling.  Does not look like it has been running for long. AC is not on. If HI coolant fan is on, high speed relay is probably stuck on.

ps is 72 degrees C,  162 F.

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41 minutes ago, DPS.01 said:

ED04 show 72 degrees…also not sure why OXY is highlighted

I believe that is Celsius. About 160* F. Still not warm enough to go into closed loop or turn on fans. I don't think the cooling fan should running. Go to "ECM Outputs", look at E009 and E010 and see if the ECM is commanding the fans to run. I expect Padgett is right about a stuck relay.

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Completely missed the C to F. 

I will look into the stuck relay, but I am confused regarding the fan powering off when the ignition is turned off.  If the relay was stuck I would think the fan would still be running even with the ignition off. 
 

Thanks for the response. 

going to look for some schematics. 

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I will check E009 and E010 on ECM outputs.  I will try that tomorrow, if not it will have to wait till later in the week. 
 

thanks for the direction. 

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I think 216 Fahrenheit is the trigger temp for the fan to activate. I wonder what temp is showing on the gauges screen display when the fan kicks on and how far below 216 it would normally shut off. 

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28 minutes ago, Padgett said:

Well that is open loop. OXY on steady just means the O2 is not cycling.  Does not look like it has been running for long. AC is not on. If HI coolant fan is on, high speed relay is probably stuck on.

ps is 72 degrees C,  162 F.

Correct AC is not on. 
Vehicle has “low refrigerant level”… on the list to fix. 
 

Vehicle was idling for about :20 minutes or so before the high speed fan turned on. 
 

will try to get info from the gages screen for temp indicated when fans go to high. 

Edited by DPS.01
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21 minutes ago, DPS.01 said:

I will look into the stuck relay, but I am confused regarding the fan powering off when the ignition is turned off.  If the relay was stuck I would think the fan would still be running even with the ignition off. 

What you are saying makes sense. Cooling fan power is hot all the time but cooling fan relay control is only powered when the key is in the run  position. I think the next step is to check diagnostics to see if the ECM is picking up the cooling fan relay(s) for some reason.

 

cooling_fan_diagram-89.jpg

 

 

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Note: 89 is different from 88. For 89 LO is both fans in series. HI is both fans in parallel. Ground is applied though two connections to the ECM.

 

Do you have one fan on or both ?

Edited by Padgett
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…just able to get back to this. 
the car is a 1989.  It has two fans, one pusher and one puller. 
 

now that I am able to access the car, I will try the recommendations provided. 

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This morning I let the car idle for about :45 minutes. 
 

At first the temperature would cycle between 98C and 102C on ED04 (this also corresponded to 208F and 216F on the gauges screen).  The electric cooling fans were not running at this point, and the AC was off. 
 

At some point the low speed cooling fans energized (both fans in low). The ED04 temperature dropped to 96-97C and remained there.  The fans did not cycle at this point and remained running in low speed. 
 

F89E0F9C-D7F5-410A-9E82-70B53B9D45BD.thumb.jpeg.0940d23bb41f716ce7acfb70e1485d16.jpegF4C51513-0EE7-4589-B4B5-BC120D8F58BD.thumb.jpeg.0df9625c1b2abcbb6f6aa69c7c42dda1.jpeg

 

I am not understanding the diagnostic system well enough at this point to figure out how to command the fans on / off in high or low speed or to tell if the ECM is commanding them to do so.  I need to educate myself some more…

 

… now it’s raining…. Weather Delay. 
 

I did figure out what I was doing wrong, and was able to command the low and high speed fans “on and off” from the override menu…

 

still have not been able to replicate the high speed fan operating and then not turning off….

Edited by DPS.01
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On 5/14/2022 at 6:51 PM, Ronnie said:

I believe that is Celsius. About 160* F. Still not warm enough to go into closed loop or turn on fans. I don't think the cooling fan should running. Go to "ECM Outputs", look at E009 and E010 and see if the ECM is commanding the fans to run. I expect Padgett is right about a stuck relay.

I tried this with the engine running on my car this morning for the first time.  I found that the diagnostics will not show you if the fans are on or off with the engine running as you discovered.  Where the four dashes are on you screen will have "HI" or LO" displayed when the engine isn't running to indicate if the fans are on or off. I don't know why that is.

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OK first download the diagnostic booklet from Ronny's site.

diageo.jpg.8bec9ebc8407610bfbec5fc57dfea4ff.jpg

Next those are the fan RELAYS not the fans themselves. Need to understand how the relays (schematic above) and the ECM control the fan speeds. The bars mean it is not able to display the commands.

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30 minutes ago, Ronnie said:

I tried this with the engine running on my car this morning for the first time.  I found that the diagnostics will not show you if the fans are on or off with the engine running as you discovered.  Where the four dashes are on you screen will have "HI" or LO" displayed when the engine isn't running to indicate if the fans are on or off. I don't know why that is.

 

1 hour ago, DPS.01 said:

This morning I let the car idle for about :45 minutes. 
 

At first the temperature would cycle between 98C and 102C on ED04 (this also corresponded to 208F and 216F on the gauges screen).  The electric cooling fans were not running at this point, and the AC was off. 
 

At some point the low speed cooling fans energized (both fans in low). The ED04 temperature dropped to 96-97C and remained there.  The fans did not cycle at this point and remained running in low speed. 
 

F89E0F9C-D7F5-410A-9E82-70B53B9D45BD.thumb.jpeg.0940d23bb41f716ce7acfb70e1485d16.jpegF4C51513-0EE7-4589-B4B5-BC120D8F58BD.thumb.jpeg.0df9625c1b2abcbb6f6aa69c7c42dda1.jpeg

 

I am not understanding the diagnostic system well enough at this point to figure out how to command the fans on / off in high or low speed or to tell if the ECM is commanding them to do so.  I need to educate myself some more…

 

… now it’s raining…. Weather Delay. 
 

I did figure out what I was doing wrong, and was able to command the low and high speed fans “on and off” from the override menu…

 

still have not been able to replicate the high speed fan operating and then not turning off….

Rain delay is over. 
Reatta idled for about :45 minutes or so. 
I was not paying attention to it so I don’t know when the fans kicked on. 
 

went to high speed and stayed running. 
gage display reads 170F and fan remains in high. 
 

I think I will get a new relay to try and eliminate that. 
 

 

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10 minutes ago, Padgett said:

OK first download the diagnostic booklet from Ronny's site.

diageo.jpg.8bec9ebc8407610bfbec5fc57dfea4ff.jpg

Next those are the fan RELAYS not the fans themselves. Need to understand how the relays (schematic above) and the ECM control the fan speeds. The bars mean it is not able to display the commands.

Understood & Thanks. 
I did download the diagnostic book.

I did verify that I could command the low and high speed fans on and off using the override ecm screen with the engine off as Ronnie indicated. 
 

the relays seem to cycle ok with the override. 
 

somewhere along the line the fans are not commanded off when temperatures drop.

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