My heater wasn't blowing hot air so after taking it to the shop they said it was the radiator and put a new one in. Then one week later, my Blower Motor doesn't work. Are they related in anyway?

Also check for a bad relay.

My 2007 Exterra just started doing the same thing. But sometimes it works and sometimes it does not. What do you think it could be. I a blower motor expensive?

If you only have high speed it'll be the blower motor resistor or sometimes called amplifier in some models with auto air.

I would say it is the relay switch located under the glovebox. I purchased one at the dealership for 75 bucks and installed in about 30 minutes and mine works perfect!

I put a new blower motor in and a relay switch and mine still doesn't work.