300CE - Hot Air Blowing into the Car !

The Story... One morning as I was on my way to work, I tried opening the doors with the remote (The car is fitted with a anti-hijack alarm - immobiliser unit... it is Johanessburg South Africa ???) and nothing happenned, the car did not start. I was sure that the alarm unit was faulty.

I called the alarm service centre and they replaced the unit. However, on further inspection once they removed the cubby cover they stated that the power wire (red/black) was dead.

Also, none of the aircon buttons now work.... and very hot air is blowing into the car even though the heater is off. The centre control panel, housing the aircon knobbs and the radio/frontloader CD gets exceptionally HOT !!!. To the extent that if I play a CD the display reads CD HOT ... that is how hot the panel gets...

I took it to an auto electrician and it seemed that they were not prepared to remove the dash or work on it ... they said it was an 8 hour job ???

Previously, I had written in explaining that my oil level indicator light came on for no apparent reason ... according to the auto electrician they said that the problem could be from the same source...

I had checked all the fuses and that is OK !

WHAT COULD THE PROBLEM BE ???

Hot air blowing into the car is a symptom of the dead control unit - all flaps and settings defaults to HOT -- probably because the winters are so cold (other than here and Australia ...) that cold air is not a good default setting for sub zero temperatures.

anyway, fuse 7 (on my W124) powers the control unit - check the fuse out again ...

could be that the control unit popped because of the faulty alarm unit - who knows what wires were used for powering the alarm system ... is it an OEM alarm or aftermarket ? OEM will be within MBSA's scope to fix ...

So far it does not look too good - control unit is probably shot and it's quite expensive from MB. Try Majestic in downtown Johannesburg for a used unit ...


BTW, the hot centre console is 'normal' considering the ample amount of heated air, combined with 25+ outside temperature, entering the car .... shut off the fan, close the vents let the air flow via the defrost vents - a bit more bearable. Be glad your not in Messina !!!

BTW 2 Does the aux fan work with the air con on and the engine temp above 100deg C ? If it doesn't, you probably have a power related problem from fuse 7 downstream.

good luck
L

Thanks for the advise...

The problem was a connection from the fuse box to the power wire... that was sorted out reasonably quickly...

Do you think that R550.00 ($ 47.00) was reasonable including parts and labour?