MKR1010WIFI and motor carrier

Hello all. I am a big time newb so please forgive me if I ask what has already been asked but I'm not sure how to phrase the question.
Here goes
I have an MKR1010wifi and a motor carrier. I am using it to control a bot using rc. I use the pulsein on pins 1-4. It works fine when the motor carrier is not connected. As soon as I connect it stops reading the pulse in.
Is this just the pins being used for something else?

Thank you
Andy