Radiator fan inop
10-28-2022 | 09:49 AM
#12
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Joined: 12-26-2014
Posts: 68
From: Crestview, FL
I was trying to explain why my question about 220F was important. The question being is it the AC or the temperature or both that don't work.
Do you often monitor the cooling fan? How do you know it was working before the car wash?
The AC compressor will not turn on unless the blower is on, the Dark Green wire tells the computer that the blower is on. Probably not important here.
You could hot wire the cooling fan to see if it works. I suspect an error in installation.
The Dark Green wire from the ECM to the cooling fan relay turns the fan on and off It depends on several inputs.
Do you often monitor the cooling fan? How do you know it was working before the car wash?
The AC compressor will not turn on unless the blower is on, the Dark Green wire tells the computer that the blower is on. Probably not important here.
You could hot wire the cooling fan to see if it works. I suspect an error in installation.
The Dark Green wire from the ECM to the cooling fan relay turns the fan on and off It depends on several inputs.
10-28-2022 | 10:33 AM
#15
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Joined: 01-23-2009
Posts: 25,339
From: Fredericksburg,VA
I was a mechanic for 50 years
I doubt that the fan could possibly have any effect on the ECM; that is why there is a relay and fuse.
There is a diode in the compressor circuit , The fan relay might have an internal diode. I would get a new relay..
I don't know how a carwash could be the trigger.
How about checking ground continuity between the relay and ECM. Did you mean that you jumped ground to the relay and that triggered the fan, like test the relay not the fan.
10-28-2022 | 12:01 PM
#16
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Member
Joined: 12-26-2014
Posts: 68
From: Crestview, FL
That explains blaming computers.
I doubt that the fan could possibly have any effect on the ECM; that is why there is a relay and fuse.
There is a diode in the compressor circuit , The fan relay might have an internal diode. I would get a new relay..
I don't know how a carwash could be the trigger.
How about checking ground continuity between the relay and ECM. Did you mean that you jumped ground to the relay and that triggered the fan, like test the relay not the fan.
I doubt that the fan could possibly have any effect on the ECM; that is why there is a relay and fuse.
There is a diode in the compressor circuit , The fan relay might have an internal diode. I would get a new relay..
I don't know how a carwash could be the trigger.
How about checking ground continuity between the relay and ECM. Did you mean that you jumped ground to the relay and that triggered the fan, like test the relay not the fan.
10-28-2022 | 02:59 PM
#17
Senior Member
Joined: 03-29-2022
Posts: 1,100
From: Davison MI
The reason I know it was working before the car wash is the a/c was cooling before the car wash and after it stopped cooling. The compressor is running but without the fan it is just cool air, not cold. I did jump the hot and fan terminals on the fan relay and the fan comes on so the wiring to the fan has to be good. I just wonder if when the fan went bad did it damage the ecm? Something is not triggering the ground on the relay. I am going to try and find the wire from the ecm going to the fan relay and see if it is good. I see some of the years shows a diode in that wire and some don't on the wiring diagram but I don't know which years do or if that is the diode in the fuse box which is good. I was a mechanic for 50 years but these new cars stump me sometimes.
You also say the fan runs when you trip the relay and yet you replaced the fan?
Since long before computerized stuff we used diodes in all electric motors to filter the high voltage spike you get when powering or cutting power.
10-28-2022 | 09:05 PM
#18
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Member
Joined: 12-26-2014
Posts: 68
From: Crestview, FL
OK. So what happened at the car wash that could have caused your problem? Can;t think of anything than call it a coincidence.
You also say the fan runs when you trip the relay and yet you replaced the fan?
Since long before computerized stuff we used diodes in all electric motors to filter the high voltage spike you get when powering or cutting power.
You also say the fan runs when you trip the relay and yet you replaced the fan?
Since long before computerized stuff we used diodes in all electric motors to filter the high voltage spike you get when powering or cutting power.
10-30-2022 | 02:14 PM
#19
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Member
Joined: 12-26-2014
Posts: 68
From: Crestview, FL
Well after more troubleshooting this is what I've found. The fan trigger wire from the ecm has continuity to the fuse box but not through the box. So I need a fuse box for sure. The a/c compressor clutch is burnt up so I need a compressor. The fan does not come on at 200 degrees which I assume is due to the fuse box. Now I just have to decide if a car with 215 thousand miles is worth the expense and work or if it's junk time.
