Cooling and Electrical

[dupontj]

My problems all started with the Cooling Fan Control Module failing (continuously ran and killed the battery). I purchased a used control module and had to replace the battery (it was five years old anyway). The control module seems to work fine. However, the battery drains overnight. I tested for parasitic draw, was pulling about 3 amps constant. I pulled fuses and found #20 (Transmission Shifter Solenoid / Keyless Keypad) dropped it to about 1 amp. When I plugged it back in, it jumped to 10 and came back down to 3. That was the only fuse that had any significant effect. Also, after replacing the control module the temp gauge periodically jumps to hot and immediately levels back to midpoint. The fuel gauge once registered absolute empty/no mile range but had about 8 gallons in the tank.

Any common denominator in all of this or am I dealing with separate issues that coincidentally happened after the control module went bad and was replaced? Someone had mentioned to me the temp sensor provides data to the ECM and maybe this is a possibility.

 

[76FoMoCo]

Rubbed wire?

 

[xekrubx]

Rubbed wire?

Similar but maybe chewed? Did this car sit for any length of time?

 

[Texas Marauder]

Fuse 20 inside or outside? What year?

 

[dupontj]

Similar but maybe chewed? Did this car sit for any length of time?

The car sits no more than two days.

 

[dupontj]

Fuse 20 inside or outside? What year?

Inside fuse. 2010 SHO

 

[Texas Marauder]

Ok, my reference shows fuse 20 powers DLC pin 16 and adjustable pedal switch. Fuse 5 powers floor shifter and keyless entry pad illumination W/O intelligent access. Verify your results again.





Check for voltage at the floor shifter solenoid (C3245 pin 1) with the car off. Check if you can shift out of park with the car off. If either of these exist you likely have a failed BCM.

 

[dupontj]

Ok, my reference shows fuse 20 powers DLC pin 16 and adjustable pedal switch. Fuse 5 powers floor shifter and keyless entry pad illumination W/O intelligent access. Verify your results again.

View attachment 88376

View attachment 88377

Check for voltage at the floor shifter solenoid (C3245 pin 1) with the car off. Check if you can shift out of park with the car off. If either of these exist you likely have a failed BCM.

Per Owner's Manual, Fuse 20 definitely as I stated. I cannot shift out of park with car off.

 

[Texas Marauder]

Per the wiring diagram (posted above) and the owner's manual (3rd printing) at Ford's website, the fuses are exactly as I described. Maybe your manual is wrong. If it is indeed fuse 20, try unplugging the adjustable pedal switch. Also unplug anything plugged into the DLC.

 

[kryptto]

https://knowhow.napaonline.com/bad-body-control-module-heres-tell/

 

[dupontj]

Thanks. That's crazy but I guess there could be a misprint. Can you point me in the right direction to unplug all you described?

Per the wiring diagram (posted above) and the owner's manual (3rd printing) at Ford's website, the fuses are exactly as I described. Maybe your manual is wrong. If it is indeed fuse 20, try unplugging the adjustable pedal switch. Also unplug anything plugged into the DLC.

 

[Texas Marauder]

The pedal switch is on the left side of the steering column, below the turn signal lever. You'll need to remove the column shroud to access the plug. The pedal switch should not draw any power in the neutral position unless it is shorted closed. The DLC is the plug under the dash that a scan tool connects to, sometimes called the OBD2 port. The DLC, by itself, does not draw any power. Anything plugged into it will draw some power. Was any accessory added that might be tapped into fuse 20?

As you can see, fuse 20 goes to the pedal switch. With memory is similar. If the switch is shorted forward, it will draw power and the pedals would be all the way forward, which you would normally not notice.

 

[dupontj]

https://knowhow.napaonline.com/bad-body-control-module-heres-tell/

That's an interesting diagnosis. Thanks!

 

[dupontj]

The pedal switch is on the left side of the steering column, below the turn signal lever. You'll need to remove the column shroud to access the plug. The pedal switch should not draw any power in the neutral position unless it is shorted closed. The DLC is the plug under the dash that a scan tool connects to, sometimes called the OBD2 port. The DLC, by itself, does not draw any power. Anything plugged into it will draw some power. Was any accessory added that might be tapped into fuse 20?

As you can see, fuse 20 goes to the pedal switch. With memory is similar. If the switch is shorted forward, it will draw power and the pedals would be all the way forward, which you would normally not notice.

View attachment 88511

No accessories added to fuse 20. Thanks for the schematic. I will be looking into this next.
Any theories on why the Temp Gauge jumps to Hot and back down to mid-range? The more I think through this, the initial problem was the Cooling Fan Control Module. The fans would run at high speed when not necessary, and then once the fans did not turn off and killed the battery. The fans are powered through the control module. What doesn't make sense here is supply power to the control module didn't cut off thereby constantly powering the fans. Is it possible a temp sensor went bad and continuously fed bad data to the control module?

 

[Texas Marauder]

The temp gauge gets it's signal thru the HS CAN network from the PCM. Using a scan tool, you need to read the ECT Pid that the PCM is seeing and compare to the temp gauge. If the ECT is steady and the temp gauge is not, there is likely a problem with the instrument cluster. If the ECT varies with the temp gauge, it's likely the ECT sensor causing the fluctuation.

The fan module has constant power and is controlled by the PCM. If the fans run when the engine is off, there is a problem with the control module. When the engine is running there are many parameters that influence the fans. Ambient temp, speed, A/C pressure, ECT are some. Example my car, ambient 103F, 77mph, ECT 180F both low and high fan on. Lower ambient to 90F, 75mph, ECT 176F only low fan.

 

[dupontj]

The temp gauge gets it's signal thru the HS CAN network from the PCM. Using a scan tool, you need to read the ECT Pid that the PCM is seeing and compare to the temp gauge. If the ECT is steady and the temp gauge is not, there is likely a problem with the instrument cluster. If the ECT varies with the temp gauge, it's likely the ECT sensor causing the fluctuation.

The fan module has constant power and is controlled by the PCM. If the fans run when the engine is off, there is a problem with the control module. When the engine is running there are many parameters that influence the fans. Ambient temp, speed, A/C pressure, ECT are some. Example my car, ambient 103F, 77mph, ECT 180F both low and high fan on. Lower ambient to 90F, 75mph, ECT 176F only low fan.

View attachment 88530

I think I found the culprit to the Temp Gauge jumping up and back down to normal range. The coolant reservoir was low. I added about a half gallon to get it back into range. No more issues. The car is smart enough to tell you when your windshield washer is low, but not smart enough to tell you when the coolant is low.

 

[76FoMoCo]

I think I found the culprit to the Temp Gauge jumping up and back down to normal range. The coolant reservoir was low. I added about a half gallon to get it back into range. No more issues. The car is smart enough to tell you when your windshield washer is low, but not smart enough to tell you when the coolant is low.

And your dipstick for oil is not smart either fyi