REST Icon appeared.

[RaptorStrike]

The rest icon appeared in my car last time I drive (forgot I had taken the pic until I saw it whilst looking through my photos)

I've no idea how to activate/deactivate and can't find it in the owner manual.

Any help would be appreciated.

[Qsilver7]

If it's like the REST feature that was on my e38/e39/e53/f06...it is the RESIDUAL HEAT feature of the IHKA system. It uses the stored residual heat from the car's engine cooling system that allows you to operate the HVAC blower to blow warm air into the cabin without the engine running. Like if you are stopped at a railroad crossing or if you're running errands in the fall/winter/spring and its cool outside but you'd like to keep the cabin warm while you run in and take care of business. The system eventually shuts down if you don't return after approx 15-16 minutes.

The IHKA panel used to have a specific REST button...but then around the 1998/99 model year...they incorporated it into the MAX button...and on my F06 it is initiated when the fan speed button is pressed when the car is in the "radio-ready state" (engine is off but the control modules are still powered).

On the new IHKA control panel...I'm not exactly sure how you initiate it...so pull out your owners manual and look for RESIDUAL HEAT to see how to turn it on...and report back.

Below is the description and requirements for activating the REST feature from the F chassis models...which isn't much different than my old E chassis models. I'm sure the G chassis models will be just as similar:

[RaptorStrike]

Originally Posted by Qsilver7

If it's like the REST feature that was on my e38/e39/e53/f06...it is the RESIDUAL HEAT feature of the IHKA system. It uses the stored residual heat from the car's engine cooling system that allows you to operate the HVAC blower to blow warm air into the cabin without the engine running. Like if you are stopped at a railroad crossing or if you're running errands in the fall/winter/spring and its cool outside but you'd like to keep the cabin warm while you run in and take care of business. The system eventually shuts down if you don't return after approx 15-16 minutes.

The IHKA panel used to have a specific REST button...but then around the 1998/99 model year...they incorporated it into the MAX button...and on my F06 it is initiated when the fan speed button is pressed when the car is in the "radio-ready state" (engine is off but the control modules are still powered).

On the new IHKA control panel...I'm not exactly sure how you initiate it...so pull out your owners manual and look for RESIDUAL HEAT to see how to turn it on...and report back.

Below is the description and requirements for activating the REST feature from the F chassis models...which isn't much different than my old E chassis models. I'm sure the G chassis models will be just as similar:

It's not in the owners manual.

Even the digital drivers guide app which is linked to my chassis no. doesn't show it.

[Pelo Cat]

Look for ‘independent ventilation’, it should show up there.

I can’t add a picture right now but you can find it in the manual that way. Hope this helps.

Safe travels everyone.

[RaptorStrike]

Originally Posted by Pelo Cat

Look for ‘independent ventilation’, it should show up there.

I can’t add a picture right now but you can find it in the manual that way. Hope this helps.

Safe travels everyone.

Found it. Thank you.

No idea why it showed that day as I hadn't pressed anything. I had parked up and stopped the engine. Was about to get out the car and noticed it was displayed.

Thanks again

[STR3T]

Had the REST feature in two prior Touareg’s and thought I’d seen a button for it on a 5-series a few years back. Was surprised when I didn’t see it in my 750 when I got this summer.

So does the 2016MY have it...activate it by pressing the higher fan speed button when engine is off?

[RaptorStrike]

Originally Posted by STR3T

Had the REST feature in two prior Touareg's and thought I'd seen a button for it on a 5-series a few years back. Was surprised when I didn't see it in my 750 when I got this summer.

So does the 2016MY have it...activate it by pressing the higher fan speed button when engine is off?

My MY2018 doesn't have a button and wasn't aware of how to activate it.

[STR3T]

Nice...the online manual under Parked Car Ventilation:

Switching on/off directly
There are different ways to switch the system on or off.

(Larger fan symbol here, it didn’t copy) symbol on the automatic climate control signals to switched on system.

REST is displayed on the automatic climate control. The residual engine heat is used.

The system switches off automatically after a certain period of time. The system continues to run for some time after being switched off.

Everything I see on Independent Ventilation is more to cool the car by running fans and venting hot air out.

[Qsilver7]

So can we conclude that the G chassis is like the F chassis and REST is initiated by pressing the fan speed button (like mentioned in post #2)? And as mentioned already...BMW ceased using a dedicated REST button back in 1998/99...and incorporated the feature into the MAX button...which depends on ambient temperature as to how the system will function (below 59° F = REST feature & above 61° F= MAX feature)...and now seems to have moved the REST initiation to the fan speed button.

FYI, it also requires certain conditions to implement this feature...like the engine not running, it has to be below a specific ambient temp and car has to up to normal operating temperatures (so that there's available heat for the air to be warmed), and the car's battery has to have enough charge.

[STR3T]

That’s my take yes...but I didn’t drive anywhere today so no proof yet!

Success: didn’t even drive far, coolant temp was only half way to mid...shut engine off, pushed the ‘increase’ fan speed once and REST lit up and I could hear the fans kick in. That was back at home when I remembered to check this out so I then hit reduce speed fan until it shut down. But yeah...sweet feature that I’d bet 75% or more don’t know they have.

[Qsilver7]

...thanks for the update. And I'd bet the percentage is higher in regards to knowing about this feature...I'd say it's probably around 90%.

Reason why I say percentage is higher:

1. When there was an actual REST button on the IHKA...owners would always ask what it was for because when they pressed it nothing happened. And nothing happened because they usually pressed the button when the engine was running...which doesn't engage/initiate the REST feature. So many that even attempted to try it...thought it didn't do anything.
2. When BMW moved the initiation to the MAX button...basically the same thing happened...plus if they didn't read about it in the owners manual or ran across the topic on the forums...they assumed that it was only a single function button and worked in the summer/heat to only provide a pre-programmed setting for the AC.
3. And know that it is initiated with the fan speed button...again, unless you read the owners manual or run across a discussion of it (like this thread)...most owners don't know that the feature exists...especially if they are new to BMW and never ran across this feature in previous BMWs they owned.

[STR3T]

Totally agree...could be 90% unaware of this really ‘nice to have’ feature...and what a great time of year to get this thread going!

Damn makes me wonder if this was a feature in my 435i that went completely unused during my ownership...lol.

Thanks to Raptor for accidentally hitting the fan button...or some such action

[RaptorStrike]

Originally Posted by STR3T

Totally agree...could be 90% unaware of this really ‘nice to have’ feature...and what a great time of year to get this thread going!

Damn makes me wonder if this was a feature in my 435i that went completely unused during my ownership...lol.

Thanks to Raptor for accidentally hitting the fan button...or some such action

Lol, you're welcome. Not sure how I did it. But at least I know how it works now.

In my Mercedes I had a dedicated button for it.

I wonder why BMW chose to remove the button and incorporate it into another function?

[Qsilver7]

Just remember...the REST feature (use in cold weather) and the Parked Ventilation feature (use in hot weather) perform the same function...at least it does on my f06. I also use this in the summer on really hot days...when I'm parking in a dark location that doesn't have a lot of air movement (like my garage or parked face-in toward a concrete wall). This helps evaporate moisture and condensate & facilitates the prevention of the growth of bacteria and mold (which loves dark damp places) that can cause that AC funky smell that many owners experience when they first turn on the system.

When temps are above the REST threshold (approx 71° F)...if you press the fan speed button...it will keep the HVAC blower running to keep air circulating through the cabin on those hot summer days. So if you're running errands and you don't want to come back to an oven where the interior has risen to 180° F ...you can do the same thing you did in the winter with the REST feature.

BTW, I got caught at a long train (it actually came to a complete stop at one point) Monday night...and laughed to myself as to if I was jinxed due to just talking about the REST feature.

[STR3T]

One other key difference is that the Parked Ventilation feature can be enabled by digging into the iDrive menu and programming a certain time for it to kick-off...or simply by using the BMW app for your vehicle.

I don't believe REST can be enabled in those ways...

Oh and got real world test in last night...ran into a store and my son stayed in the car. Was ~20F outside, he said it lasted about 10 minutes before shutting itself off.

[Pelo Cat]

Originally Posted by STR3T

Nice...the online manual under Parked Car Ventilation:

<snip>

Everything I see on Independent Ventilation is more to cool the car by running fans and venting hot air out.

Think there must be different versions for different countries, I can't find anything under parked car ventilation for example but again likely just country versions differing.

Under the UK VIN specific manual for my car, the following comes up for independent ventilation (and shows the conditions as well as the various ways to activate it for both heating and cooling). Now back home with a proper computer so can post screenshots! Safe travels everyone, hope this helps with the details of how and when it will work (regardless of where one is located!)

[Pelo Cat]

Originally Posted by STR3T

One other key difference is that the Parked Ventilation feature can be enabled by digging into the iDrive menu and programming a certain time for it to kick-off...or simply by using the BMW app for your vehicle.

I don't believe REST can be enabled in those ways...

Oh and got real world test in last night...ran into a store and my son stayed in the car. Was ~20F outside, he said it lasted about 10 minutes before shutting itself off.

Yes, agreed, rest (heat) won't work with timer as no residual heat to use so the timing aspects are for cooling only unfortunately. (at least in the UK, I believe some countries can order the car with the ability to warm the car using an additional optional heater as well but not available/legal in the UK).

Your son was right, it runs for 8 minutes then shuts down to save the battery.

Safe travels.

[Qsilver7]

The length of the REST feature blowing heat into the cabin varies depending on how many consumers are on as well as the ambient temperature. REST stands for "residual"...so the feature is using a limited resource that is being affected by the battery's voltage and the ambient temperature's affect on the source of heat (the engine's coolant).

The feature is designed to turn the blower off before draining the battery to the point the car won't start. So if you've initiated REST...it will run a bit longer if the engine is off as well as the headlights and radio or seat heaters etc. Just as it will probably run longer if the ambient temp is higher (45°F vs 15°F).

If you leave passengers in the car and turn off the engine, but leave the radio on (or leave the car in the "radio-ready"/"standby-state") and the seat heaters are on, too...then the REST time interval will be shorter.