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Discussion Starter #1
On intermittent occasions, after completely turning off the engine, all accessories and leaving vehicle parked, we've noticed that
1) the radiator fan starts on it's own, and
2) the residual heat fan inside the vehicle turns itself on.

Never together, but each will run indefinitely until someone notices. Inserting the key into ignition will usually turn off radiator fan. Opening door and pushing the A/C button will turn off the residual heat fan - sometimes just opening the door will work. Very intermittent - 1-2 times per month.

Is anyone having similar problems? Dealer claims radiator fan running is normal. Hard to believe, without explanation why this might occur and under what circumstances. Not over-heating and has happened in -5C degree temperature. Residual heat fan is also a mystery.

Our prior 2008 ML320 CDI never did this.
 

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Discussion Starter #2
Residual heat fan - response from MB Canada

According to MB Canada - Residual heat fan (ie. A/C button activated when engine off) is programmed to run on it's own to reduce condensation and help eliminate odour, mold, or rusting within heater core in 2010 ML, GL and RL vehicles. Fan is programmed to run for max 30 minutes or the following conditions:
1. Temperature of heater core drops below 72F.
2. Any Voltage drop from opening doors, locking doors with remote, or similar.

For anyone worried about battery being drained because of this - MB has designed system to monitor battery condition while fan is running and stop the fan if battery appears to be draining towards "dead" status.

MB should make this information and level of detail available in the owners manual.
 

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Discussion Starter #4
Good point. Can't speak for MB, but maybe it's more about reducing condensation that might lead to musty smell and mold within the heater box area/vents over long term. As long as the fan running won't drain the battery, we'll learn to get used to it - even though it seems pretty awkward when you first see it happening. Even the Service manager at our dealer, who drives an 2010 ML350 demo thought something was wrong at first, until they called and found out what was really happening.
 
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