2013 Fiesta blower motor (power to relay coil)

[Minnie79]

Hello. My friend has a 2013 Fiesta. The blower motor recently quit working. As time and weather permits (seems it’s rained all summer so far) I’ve been trying to figure it out. Here’s what I’ve done so far.

The car has the standard control head with no display. Does not work on any speed, heat or AC. Kinda rules out the resistor.

Turning the fan on and off or changing speeds does not make the relay click. Relay tests good, clicks with battery voltage and has continuity across terminals during that time. Switched side of relay socket has 12v available at all times.

Also checked cooling fan relay which was right next to it and it tested the same. Swapped them with no difference.

Blower fuse is good.

Pulled connector from blower motor, and no voltage at connector with ignition on and blower control on, any speed.

I did all this last week. Today in the rain I had to fix a coolant line so I checked some more things.

I bridged the switched relay terminals to fake the relay being on. The blower motor ran like normal on all speeds, operated by the control head.

So I checked the voltage at the relay coil with the key and blower control on. Across the terminals started at 7 volts, and gradually dropped to 5 volts. By then I gave up, it had slowed but was still slowly dropping. Then individually to the battery, the power side was a little higher by 100-150mv. The ground side had about 100-150 mv. Not sure if this is proper, but it was barely a drop in the bucket. Isn’t this supposed to run at 12v? That would explain why it’s not enough to fire the relay coil.

So without a schematic, what’s next to check? Where does the relay coil power come from and how do I check it? BTW, the cooling fan relay is right next to it, and that runs fine. It was running today.

 

[Handy Andy]

The line from the Blower to the BCM or to the Controller (More than likely the controller) - you'll need to do a continuity check on it.

Notice the "two Ground wires" running from the Controller - look for those in two places, under the dash bolted to the firewall just above the Brake pedal and or the ones on the Floorboards under the carpet by the Front Seats.



These are for the MANUAL Climate Control System