seached but couldn't find anything about "RES" button on a/c - BMW 3-Series (E90 E92) Forum

wins76 · 01-14-2013, 02:39 PM

Just wondering what's that button (RES) on the A/C unit for and how to use it?

I tried pressing the button and nothing happends. Do I have to wait the car to fully warm up before it work?

marcus321 · 01-14-2013, 02:46 PM

REST allows residual heat from the engine to filter into the cabin while the engine is off to keep the car warm without keeping it running. It's useful for people who might for example jump out of their car briefly while it's cold outside and want it to stay warm for when they return shortly after, or for people who need to sit waiting in their car for a short period of time.

A car thats barely heated up wont have much residual heat left so it doesnt do much in that scenario.

SteveMD · 01-14-2013, 02:46 PM

Residual Heat Mode?

See here: http://screencast.com/t/0pmW3h1E

cmyk · 01-14-2013, 02:48 PM

It lets RESidual heat from the engine through the vents, keeping the cabin warm while the engine is off. Handy when you're waiting on someone and don't want to keep the car running. IIRC this button was replaced by the ALL control in later models, which sets both sides of the climate control to the same temp.

ETA looks like a couple people beat me to my response

Damn slow typing on my phone haha

Infidel · 01-14-2013, 02:53 PM

I believe what you are talking about is the REST button, I forget if it says REST or RES. Either way, it is residual heat mode. What it does is (with the car off) run the fan to blow any remaining heated air from the engine compartment into the cabin for a certain amount of time. 20 or 30 mins comes to mind but I may be fabricating that thought.

An example of its use would be this: freezing cold out, you drive to the grocery store and want to keep the car fairly warm for when you come back out from shopping. You park, turn off the car, hit the rest button then go about your shopping, when you come back the car is still habitable. Could also be useful to keep a pet or passenger comfy without them having the keys i guess.

335BBS · 01-14-2013, 03:44 PM

Quote:

Originally Posted by Infidel

I believe what you are talking about is the REST button, I forget if it says REST or RES. Either way, it is residual heat mode. What it does is (with the car off) run the fan to blow any remaining heated air from the engine compartment into the cabin for a certain amount of time. 20 or 30 mins comes to mind but I may be fabricating that thought.

An example of its use would be this: freezing cold out, you drive to the grocery store and want to keep the car fairly warm for when you come back out from shopping. You park, turn off the car, hit the rest button then go about your shopping, when you come back the car is still habitable. Could also be useful to keep a pet or passenger comfy without them having the keys i guess.

That and the heated steering wheel ....two best options available to us up here.

01-14-2013, 02:39 PM	#1
wins76 Private First Class Drives: BMW 335 Join Date: Aug 2011 Location: Texas Posts: 128 iTrader: (0)	seached but couldn't find anything about "RES" button on a/c Just wondering what's that button (RES) on the A/C unit for and how to use it? I tried pressing the button and nothing happends. Do I have to wait the car to fully warm up before it work?
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01-14-2013, 02:46 PM	#3
SteveMD Colonel Drives: '09 335i, '11 GTI DSG Join Date: Dec 2005 Location: Raventown! Posts: 2,252 iTrader: (3) Garage List 2009 BMW 335i [0.00] 2006 330i [0.00]	Residual Heat Mode? See here: http://screencast.com/t/0pmW3h1E __________________ 2009 E90 335i One mod: JB4 - Best 1/4: 12.782@108.54mph 2011 VW GTI/DSG See me for Industrial Electronic Repair.

01-14-2013, 02:48 PM	#4
cmyk resident girl. Drives: 2008 335i Join Date: Dec 2011 Location: Dallas, Texas Posts: 1,004 iTrader: (1) Garage List 2008 BMW 335i [4.38]	It lets RESidual heat from the engine through the vents, keeping the cabin warm while the engine is off. Handy when you're waiting on someone and don't want to keep the car running. IIRC this button was replaced by the ALL control in later models, which sets both sides of the climate control to the same temp. ETA looks like a couple people beat me to my response Damn slow typing on my phone haha __________________ 2008 E90 335i // Black Everything // photos COBB tuned / QTP e-cutouts / Helix FMIC / cp-e DCI / AWE BOVs / Black M6 wheels + Toyo Proxes (and yes, I am a girl)

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01-14-2013, 02:46 PM	#2
marcus321 First Lieutenant Drives: e92 335i Join Date: Aug 2011 Location: Raleigh, NC Posts: 381 iTrader: (0)	REST allows residual heat from the engine to filter into the cabin while the engine is off to keep the car warm without keeping it running. It's useful for people who might for example jump out of their car briefly while it's cold outside and want it to stay warm for when they return shortly after, or for people who need to sit waiting in their car for a short period of time. A car thats barely heated up wont have much residual heat left so it doesnt do much in that scenario.

01-14-2013, 02:53 PM	#5
Infidel New Member Drives: 2006 E90 330xi MT s/p/c Join Date: Dec 2012 Location: New Hampshire, USA Posts: 18 iTrader: (0)	I believe what you are talking about is the REST button, I forget if it says REST or RES. Either way, it is residual heat mode. What it does is (with the car off) run the fan to blow any remaining heated air from the engine compartment into the cabin for a certain amount of time. 20 or 30 mins comes to mind but I may be fabricating that thought. An example of its use would be this: freezing cold out, you drive to the grocery store and want to keep the car fairly warm for when you come back out from shopping. You park, turn off the car, hit the rest button then go about your shopping, when you come back the car is still habitable. Could also be useful to keep a pet or passenger comfy without them having the keys i guess.