Cooling Fan not turning on

[rhubarb9999]

2010 4.6 .. 84K miles

So ... I was in stop and go traffic and the car overheated. The temp gauge was at zero. I assumed the temp sensor went bad and the fan did not turn on.

I replaced the temp sensor and gauge is working again. I can read OBD data and I am getting a good temp. However the fan is still not coming on.

I checked the cooling fan relay and it tests good. I checked for voltage across the relay trigger posts and its good .. so the computer is telling the fan to turn on. I jumped the power posts of the relay .. still no fan .. but there is voltage on one side.

I then checked to connector to the fan on the 'cooling fan control module/PWM' .. no voltage. Is there any other way to test the PWM before I buy a new/used one? Anything else I should check?

Is it common for the PWM to die?

 

[rhubarb9999]

I ordered a used fan controller. We shall see.

 

[mike44138]

I'm looking at the schematic for the 2009. Can't be that much different than 2010.

The basics of the circuit are high amperage 12V into the fan controller from the fan relay and a pulse width modulated feed in from the ECM to tell the controller how fast to spin the fans. Fan controller is grounded at GE01. You can't really test the PWM signal with a multimeter, you'd need a scope. PWM comes out of the ECM on terminal 54 of connector A and feeds into the fan controller on pin 2 of connector A. The PWM circuit passes through a connector labeled EC01. It's terminal 19 in the EC01 connector.

Best bet to troubleshoot the PWM without a scope would be to disconnect the fan controller and the ECM then verify that you have a low resistance path between fan controller connector A pin 2 and ECM connector A pin 54. I'd start by just unplugging EC01 and making sure there's no corrosion or damage. If the PWM path is intact, you've confirmed the 12V going into the fan controller is present when the fans should be running, the fan controller has a good ground, and the wiring to the fans and fnas themselves are good then it's either a bad ECM of bad fan controller.

Sounds like you've done this but also check: 30A ECU fuse, 10A ENG SNSR-2 fuse, 60A COOLING fuse. Clean and well attached grounds at GE01 and GE03. Proper functions of cooling fan relay and engine control relay. Condition of ECM and EC01 connectors.

Locations:
GE03 and GE01 are located on the frame rail under the fuse box and ABS module right next to the AC lines.
EC01 is the latching connector between the ECM and the firewall next to the ECM latching connectors.
JEB is a junction box located in the drivers kick panel.

Here's more detail info on the circuit...

The ECM takes input from the temperature sensor and determines when to trigger the fan relay (obviously). The triggering side of the relay goes through the "ENGINE CONTROL RELAY" in the E/R junction box. The high amp side of this relay is supplied by the 30A ECU fuse and feeds out through a 10A "ENG SNSR-2" fuse. From there it goes to the triggering side of the cooling fan relay. The grounding side of the trigger circuit passes through a junction box "JEB" and ultimately grounds at GE03 on the frame. When the cooling fan relay is engaged it feeds the cooling fan controller through the "COOLING" 60A fuse located in the fuse and relay box.

The fan controller also gets a PWM signal from the ECM. The pulses from this signal are processed and used to drive the condenser and radiator fans at the appropriate RPM. The fan controller is grounded at GE01.

Pin 1 of connector A on the fan controller should see 12V when the ECM is commanding fan on. Pin 2 of connector A should have a PWM signal when the ECM is commanding fan on. Pin 3 and 1 of connector B on the fan controller should always have a low resistance path to ground.

Terminal 4 of the fan relay should always have 12V. Terminal 2 should be grounded. Terminal 3 should see 12V when the ECM is commanding fan on.

 

[rhubarb9999]

WoW! Thank you Mike for such a detailed response. It seems I got lucky. I replaced the fan controller with a used one and it seems to have fixed the issue. I think what may have happened is that the fan controller died, stopping the fans, the car overheated and took out the temp sensor.

I am not sure what would cause the fan controller to fail. But when i took it out I noticed that one of the terminals on the fan connector was black-ish and there was a little bubbled plastic where that terminal went into the controller box. For $45 it was worth a shot and it looks like it paid off.

Thank you again for the assistance!

 

[HyunDIE]

I ordered a used fan controller. We shall see.

Hey there! Where did you happen to find the used fan controller? I’m pretty positive I may be experiencing the same issue that you had with my Genesis. Same slightly blackened, bubbled plastic and all right on the fan connector where it hooks to the fan controller. If you could point me in the direction of a used fan controller that would be awesome. Thank you!

 

[rhubarb9999]

eBay. They ranged in price from $45-75. I got the cheapest one. Worked like a charm.

Good luck.

 

[Hernameisgen]

I'm looking at the schematic for the 2009. Can't be that much different than 2010.

The basics of the circuit are high amperage 12V into the fan controller from the fan relay and a pulse width modulated feed in from the ECM to tell the controller how fast to spin the fans. Fan controller is grounded at GE01. You can't really test the PWM signal with a multimeter, you'd need a scope. PWM comes out of the ECM on terminal 54 of connector A and feeds into the fan controller on pin 2 of connector A. The PWM circuit passes through a connector labeled EC01. It's terminal 19 in the EC01 connector.

Best bet to troubleshoot the PWM without a scope would be to disconnect the fan controller and the ECM then verify that you have a low resistance path between fan controller connector A pin 2 and ECM connector A pin 54. I'd start by just unplugging EC01 and making sure there's no corrosion or damage. If the PWM path is intact, you've confirmed the 12V going into the fan controller is present when the fans should be running, the fan controller has a good ground, and the wiring to the fans and fnas themselves are good then it's either a bad ECM of bad fan controller.

Sounds like you've done this but also check: 30A ECU fuse, 10A ENG SNSR-2 fuse, 60A COOLING fuse. Clean and well attached grounds at GE01 and GE03. Proper functions of cooling fan relay and engine control relay. Condition of ECM and EC01 connectors.

Locations:
GE03 and GE01 are located on the frame rail under the fuse box and ABS module right next to the AC lines.
EC01 is the latching connector between the ECM and the firewall next to the ECM latching connectors.
JEB is a junction box located in the drivers kick panel.

Here's more detail info on the circuit...

The ECM takes input from the temperature sensor and determines when to trigger the fan relay (obviously). The triggering side of the relay goes through the "ENGINE CONTROL RELAY" in the E/R junction box. The high amp side of this relay is supplied by the 30A ECU fuse and feeds out through a 10A "ENG SNSR-2" fuse. From there it goes to the triggering side of the cooling fan relay. The grounding side of the trigger circuit passes through a junction box "JEB" and ultimately grounds at GE03 on the frame. When the cooling fan relay is engaged it feeds the cooling fan controller through the "COOLING" 60A fuse located in the fuse and relay box.

The fan controller also gets a PWM signal from the ECM. The pulses from this signal are processed and used to drive the condenser and radiator fans at the appropriate RPM. The fan controller is grounded at GE01.

Pin 1 of connector A on the fan controller should see 12V when the ECM is commanding fan on. Pin 2 of connector A should have a PWM signal when the ECM is commanding fan on. Pin 3 and 1 of connector B on the fan controller should always have a low resistance path to ground.

Terminal 4 of the fan relay should always have 12V. Terminal 2 should be grounded. Terminal 3 should see 12V when the ECM is commanding fan on.

Mike, you seem to know a lot about this stuff. My genesis coupe relay fan will not shut off even when the car is off, until the battery is drained. Trying to figure out what fuse or relay needs to be replaced. Any ideas?

 

[mike44138]

Sometimes a relay can get stuck in the on position if the contacts have fused from internal arcing. I'd pull each relay until the fan turns off, then replace that relay as a test. If it comes back on with the new relay it's most likely the fan controller. The manual for your car should list which relay controls the fans. If not, it won't hurt to pull each relay one at a time until you find the right one.

 

[Jlynn5567]

Will issues with any of this cause the car not to start?

 

[coachshawncurcio]

I'm looking at the schematic for the 2009. Can't be that much different than 2010.

The basics of the circuit are high amperage 12V into the fan controller from the fan relay and a pulse width modulated feed in from the ECM to tell the controller how fast to spin the fans. Fan controller is grounded at GE01. You can't really test the PWM signal with a multimeter, you'd need a scope. PWM comes out of the ECM on terminal 54 of connector A and feeds into the fan controller on pin 2 of connector A. The PWM circuit passes through a connector labeled EC01. It's terminal 19 in the EC01 connector.

Best bet to troubleshoot the PWM without a scope would be to disconnect the fan controller and the ECM then verify that you have a low resistance path between fan controller connector A pin 2 and ECM connector A pin 54. I'd start by just unplugging EC01 and making sure there's no corrosion or damage. If the PWM path is intact, you've confirmed the 12V going into the fan controller is present when the fans should be running, the fan controller has a good ground, and the wiring to the fans and fnas themselves are good then it's either a bad ECM of bad fan controller.

Sounds like you've done this but also check: 30A ECU fuse, 10A ENG SNSR-2 fuse, 60A COOLING fuse. Clean and well attached grounds at GE01 and GE03. Proper functions of cooling fan relay and engine control relay. Condition of ECM and EC01 connectors.

Locations:
GE03 and GE01 are located on the frame rail under the fuse box and ABS module right next to the AC lines.
EC01 is the latching connector between the ECM and the firewall next to the ECM latching connectors.
JEB is a junction box located in the drivers kick panel.

Here's more detail info on the circuit...

The ECM takes input from the temperature sensor and determines when to trigger the fan relay (obviously). The triggering side of the relay goes through the "ENGINE CONTROL RELAY" in the E/R junction box. The high amp side of this relay is supplied by the 30A ECU fuse and feeds out through a 10A "ENG SNSR-2" fuse. From there it goes to the triggering side of the cooling fan relay. The grounding side of the trigger circuit passes through a junction box "JEB" and ultimately grounds at GE03 on the frame. When the cooling fan relay is engaged it feeds the cooling fan controller through the "COOLING" 60A fuse located in the fuse and relay box.

The fan controller also gets a PWM signal from the ECM. The pulses from this signal are processed and used to drive the condenser and radiator fans at the appropriate RPM. The fan controller is grounded at GE01.

Pin 1 of connector A on the fan controller should see 12V when the ECM is commanding fan on. Pin 2 of connector A should have a PWM signal when the ECM is commanding fan on. Pin 3 and 1 of connector B on the fan controller should always have a low resistance path to ground.

Terminal 4 of the fan relay should always have 12V. Terminal 2 should be grounded. Terminal 3 should see 12V when the ECM is commanding fan on.

EC01 is the latching connector between the ECM and the firewall next to the ECM latching connectors.
I'm having trouble finding the wiring that connects to this relay at the firewall. any help would be great, as I have the relay but having trouble finding the connectors

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