At a routine check at the VX air cond unit, my technician said that the fan for the a/c unit does no come on when the air conditioning is switched on. He said one fan will turn on automatically to help cool the radiator, but the second fan will start whenevr the air cond is on. Is this true?
The tech showed me that the fan is working intermittently as you would have to tap (lightly) at the fan's motor to actually engage it to work. He assumed the fan's carbon brushes are worn out and would like to replace them at a reasonable cost.

I will be taking a road trip in july travelling bout 1000+km and will have the aircond on most of the time. If the fan for the air cond unit is working intermittently, will the car be prone to overheating?
How long should the fan be able to last before replacement? I checked the service history of the car and see that this is still the OEM installed fan in the engine bay.

Can i replace the electric fan myself as i see that this is just a fan bolted to the radiator shroud? looks easy.

Can i upgrade the electric motor to an even faster unit to promote better cooling?