Blower Fan Works Intermittently

[XXXXX]

I have a 2009 Ford Ranger 4.0L

Sometimes, but not always, the blower fan for heat and air conditioning does not work.

And then it'll come back on sometimes on its own. Sometimes it's after a minute, sometimes it's after 20.

It also seems to go on and off when I hit bumps in the road. So I'm wondering if it's not a stuck relay.

What do you guys think? The fan works fine when it does work.

Many thanks for the advice.

XXXXX

 

[Dirtman]

Does it do it at all speeds? If it only happens below full speed then check the resistor. If it happens on full speed as well it could be a dead armature on the motor. This will make a spot where, if the motor tries to start in this specific position nothing will happen but if it gets bumped to the next armature it will start running fine.

 

[Curious Hound]

Or you could have a loose connection somewhere.

 

[RonD]

lol, loose connection.............................nailed it

In the engine bay on passenger side, near the fire wall is the heater/AC box
On this box you will see a 4 wire connector, end of it looks like this: https://www.dormanproducts.com/p-46940-973-411.aspx
This is the Resistor block

Unplug it and check for corrosion, or if its loose

Blower motor relay is in the engine fuse box, open the box and look on the lid there should be a "map" of which relays are which, they are all pretty much standard automotive relays and are not expensive

You could have engine off and fan on medium(you can hear it in the engine bay) then tap on the relay to see if fan cuts out, also move wire around to see if it cuts out

 

[code_slinger]

I had the same problem. If i tapped on the fan motor it would start. Replaced the fan motor and fount the brushes were worn out. Worth a check.

 

[XXXXX]

Thanks everyone. It was indeed a loose connection, right at the blower motor itself.

Thanks for putting me on the right track!

 

[Curious Hound]

Congratulations.