if not how do l fix it and also when l switch my air con on the light comes on but nothing happens. any ideas

its a common fault with the dial controles themselves..a replacement from a brakers is nedded.dont buy new.

It will be the resister, fitted in the airflow between intake and motor,(with at least 4 wires to it) burnt out due to partially seized motor. the air-con will need to be checked, repaired and recharged by a dealer or specialist..

Yes, it will be the resistor pack, which l think on the Laguna is mounted on or near the blower motor.
Your aircon wo not work unless the fan is on and there is refridgerant in the system: most garages can check & refill nowadays, so could be linked: If it is the climate control model, both problems could be due to something more complicated - a garage job.

its a common fault, you can replace the heater control panel. The aircon might need re-gassing, so take it into a local garage, they will do it cheaper than renault.

It needs a replacement resistor pack for the problem with the fan, l had exactly the same problem with my car & it was actually quite an easy fix. A haynes manual will tell u how to do it & they r definitely available for that car. The information is also available on the net u just have to search for forums for that car.
On my car they were found just behind the glove box practically on top of the fan a new one will cost somewhere in the region of 30-40 quid a reconditioned one will be a lot less off eBay. As for the air con u may find that it needs recharging but it is hardly worth the price most garages charge for it. Plus there may well be a leak in the system & if that is the case u will have to get that fixed first.