The Heater/Blower on my grandson's Renault Megane is continuing to stop working. Pretty sure he needs an auto technician to look at it as Cavendish motors wouldn't touch it because apparently there are too many wires involved.
Any help/ recommendations would be a great help.

Is it Not Working or No Heat ?

Check the Fuse Box ?

As Mark says, does the fan blow, but just blow cold, or has the fan stopped blowing?

The "blowing but no heat" could be thermostat or head gasket...

The fan stopped blowing could be a fuse (has anything else electrical also stopped working) or it could be the motor itself has broken.

Google "Megane heater resistor" and try the first couple of links.

Could be blower resistor but it would work on number 4 the highest setting
Is this the case

thankyou foryour replies heater blows cold air ,each time repaired it blows hot air but only for a couple of hours or a day. the car is fine in every department ,no problems anywhere else.it looks as it maybe the resister .any more advice welcome. again many thanks.

common fault along with the window winder motors breaking all the time iirc.

it's a megane, common fault along with just about everything else breaking

Cheapest thing to check its the water levels. Obviously this can be Boiling water under pressure if the car has been running.

Sometimes if the water level looks ok it can need to be bleeded, (the air removed), as you could have a pocket of air at the heater matrix. And if that is so you may have to bleed all the water out and refuil it again.

If it is water related then you have to watch for water under the car as it must be leaking from some point. That's working on your assumption that it can last a few hours or a day.

I'm not sure if it is a common fault, but from what you have told us the cheapest check is the water system.

Or if you can shed some light on what the Garage or last repairer told you they fixed ?

Had it fixed opposite the pacific pub in birkenhead and it worked fine but eventually stopped working 2 months later. I then got it fixed and it stopped again after a week and then got it fixed again but stopped working the next day! i was charged the first time but not the second and third thank god! No air at all blows out whether that it is on number 1 or 4.