I have a 2001 c class when I turn on the ignition there is a clicking noise coming from the dash area it lasts for about a minute no matter what I do ...any ideas?

That is a relay doing the clicking. It sounds like you may have a short in the circuit board or the oil sending unit is bad.

It may be as simple as cleaning the battery cables.Having the clock reset shows a complete loss of voltage at one point.How old is the battery?

indicates a fuel pump problem as that is the only thing in that area that is ignition controlled or possibly the EVAP system solenoid/ valve if it is in that area
the frequency will be constant as the pump rpm is constant
the noise could be a venting noise from the EVAP in in that area
the distance of 15 km indicates that the problem is heat related as it take that long for something to over heat and cause the noise
you may get an indicator by running the fault code

replace the ignition switch as there is a problem in the contacts

Do you hear any clicking or popping noises coming from dash area when you try to change the temperature? If so, you have either a bad blend door actuator or a broken blend door. If it's just the actuator, you can find it by following the popping noise to the location. It is under the dash close to the passenger's side of the vehicle. The actuator is easy to change once you find it. If the blend door is broken, you will have to pull the dash out and remove the air plenum from inside the dash to gain access to the blend door.

Sounds like a temp door actuator. Does the heater controls move to all positions and change from hot to cold.

Flat battery.Alarm has own battery.Try booster pack or jump leads.

It could well be the battery. Charge it up for 24 Hours.
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replace the switch

There is probably a worn arm on one of the flaps inside the heater box. The noise you hear will be one of the motors turning and wearing away one of the flaps, dash out job im afraid.