Hi, Have a 500C by diesel as well as a 500 tractor and a 130 saloon.
The 500C air con turns to heater in a very short distance. When switching off, I can hear a solenoid ?
flicking back. Restart the car and air con works and then switches back to heater. Only does this when driving, not when vehicle is standing. Dealer has no idea at all and I'm very frustrated about the thing. Any ideas as to what the problem is ? Thanks

CHEMIST said:

Hi, Have a 500C by diesel as well as a 500 tractor and a 130 saloon.
The 500C air con turns to heater in a very short distance. When switching off, I can hear a solenoid ?
flicking back. Restart the car and air con works and then switches back to heater. Only does this when driving, not when vehicle is standing. Dealer has no idea at all and I'm very frustrated about the thing. Any ideas as to what the problem is ? Thanks

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Hi and welcome;

Just to clarify; is it manual AC or Climate Control?

With the ac switched OFF and the temp set to minimum are you saying the air coming from the vents is still being heated?
The ac system in a car is usually just "one way" (unlike some building systems) such it can only ever cool air never heat it .
With the ac ON and set to minimum you say it's still heating?, does the ac pump click on and off normally without any strange noises (say if the system has been over filled with refrigerant )
I would lean towards a heater box problem and or control of it.

Thanks John,
With the A/C on at it's lowest setting or say 17 degrees, we hear a sound like a solonoid after a few hundred meters and then it will blast hot air. When we stop the engine, the same noise can be heard. When we restart and drive away, the same thing happens again.
Not had the car very long and it has been with the dealer for over 2 weeks now. I have heard of a similar problem from someone in USA.

My diesel was making strange noises like yours even when I took the key out,I had it diagnosed at a air con specialist as being a faulty condenser x

CHEMIST said:

Thanks John,
With the A/C on at it's lowest setting or say 17 degrees, we hear a sound like a solonoid after a few hundred meters and then it will blast hot air. When we stop the engine, the same noise can be heard. When we restart and drive away, the same thing happens again.
Not had the car very long and it has been with the dealer for over 2 weeks now. I have heard of a similar problem from someone in USA.

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If the car is brand new can you reject it? 2 weeks to fix it indicates they don't have much clue, if its out of warranty have a ac specialist look at it?

Car is not new John. Checked again this morning, still no word from the dealer where it is now. Guess we wait a bit longer.

CHEMIST said:

Car is not new John. Checked again this morning, still no word from the dealer where it is now. Guess we wait a bit longer.

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If it is a problem with one of the actuating flaps in the airbox, you need to get this fixed properly whilst you still have some comeback against the supplying dealer.

Gaining access to the heater box is a major job on the 500; most of the interior forward of the seats has to come out, including removing both doors. Even an experienced mechanic familiar with the car will need at least a full day for the job; someone doing this at home for the first time would likely take the best part of a week.

And then you have the problem of sourcing replacement parts at a sensible price... I know of someone who was quoted north of £2000 by a Fiat dealer for changing a heater matrix on a 500 .