The r3 on the circuit board means it is a resistor.
Contrary to common experience, some precision wire-wound resistors do have their value printed on them, I would post an example but I'm typing this on my phone.
Burned resistors rarely give proper value readings so I wouldn't trust it if you do get a reading.
To reduce the risk of failure or fire you need to find an exact replacement resistor, that one looks like it may be a half or one watt rated wire-wound resistor.
Try searching for photos of your speed controller online, you may find one that shows what resistor goes there.