What is the ticking-clicking noise coming from on a 2002 Mercury Mountaineer when your Air conditioner is on and how do you fix it?

Answer 1

There is an actuator at the left rear of the passenger compartment. The plastic gears get stripped or broken and when the rear air or heat is activated a servo which is trying to make ajustments to the rear control is clunking when trying to move the gears. There is more than one actuator used in these models, so to replace it you will need to access that area and either remove the broken one and take it to the parts man or let your dealer fix it. If you can stop the clicking by changing the rear air temp, this could be the problem. This would be the ac pump cycling this is normal most of the time the only time the pump runs continuesly is when the unit is set to max ac try that first if it still cycles in high your R134a pressure my be low, I dont recall the proper pressure how ever I was able to recharge mine my self by buying the R134A and recharge kit at the auto parts store. the clerk should be able to look that info up for you. It is a relitive easy task.