Time keeps resetting after aftermarket headunit?

fccs · 02-13-2015, 10:21 PM

I installed a aftermarket double din headunit. Everything works great, steering wheel controls, sound, chime, everything. Except, if the car sits off for a while (30min-1hr) the time is reset everytime I get in and start the car. Any ideas?

Wongway · 02-13-2015, 11:18 PM

Yep... You either tapped the wrong fuse, and/or didn't bother running the constant power wire to the battery.

bmw325i · 02-14-2015, 12:42 AM

+1 it is a problem with the constant 12 volt source.

Socket · 02-14-2015, 05:23 AM

you need a flux capacitor

fccs · 02-14-2015, 07:38 PM

Where do you tap into for a constant power wire? Thought there was one on the side under the door trim piece or whatever you call it

Wongway · 02-14-2015, 11:51 PM

Quote:

Originally Posted by fccs

Where do you tap into for a constant power wire? Thought there was one on the side under the door trim piece or whatever you call it

Seriously?

Quote:

Originally Posted by Wongway

Yep... You either tapped the wrong fuse, and/or didn't bother running the constant power wire to the battery.

How much more specific could I have been?

fccs · 02-15-2015, 09:49 AM

I tapped into the constant wire up front, I guess I gotta run it to battery lol

Harry335i · 02-15-2015, 10:02 AM

If you are confused with these answers, you probably should not be working on wiring up anything in a vehicle.

ctuna · 02-15-2015, 11:00 AM

fccs · 02-15-2015, 05:59 PM

Quote:

Originally Posted by Harry335i

If you are confused with these answers, you probably should not be working on wiring up anything in a vehicle.

The 12v constant is hooked up. I didn't go directly to the battery because I see no point to when I'm taping into a wire that IS a 12v constant already.

Wongway · 02-16-2015, 12:51 AM

Quote:

Originally Posted by fccs

The 12v constant is hooked up. I didn't go directly to the battery because I see no point to when I'm taping into a wire that IS a 12v constant already.

Obviously, it's not.

mathematics · 02-16-2015, 11:55 AM

do you mean the instrument cluster time resets or the head-unit's time resets?

fccs · 02-16-2015, 06:10 PM

Quote:

Originally Posted by mathematics

do you mean the instrument cluster time resets or the head-unit's time resets?

Headunit. After like 30min or a hr of the car turned off. If I turn the car off, and go back in it to start in 20minutes it's still saved. I assume the 12v constant I have it ran to isn't good enough or something.

fccs · 02-16-2015, 07:46 PM

Found out stock headunit goes into deep sleep mode, that's why the aftermarket doesn't work by using a 12v constant up front unless it's a fuse 12v or run directly to battery. Interesting

Socket · 02-17-2015, 04:16 AM

.

bmw325i · 02-17-2015, 08:49 AM

Quote:

Originally Posted by fccs

Headunit. After like 30min or a hr of the car turned off. If I turn the car off, and go back in it to start in 20minutes it's still saved. I assume the 12v constant I have it ran to isn't good enough or something.

Just run a wire to the battery and be done with it. We already answered your question.

jwzimm · 02-17-2015, 11:36 AM

There are several power buses in the car. Each is controlled by the CAS and relays. Very little receives a constant 12V supply to preserve battery life. Lots of control modules are powered off the bus that goes dark after about 30 minutes (referred to the car going to sleep). There is also a bus that provides constant 12V power unless the CAS detects the battery is draining beyond the point where the car can start.

Tapping the battery directly can be an issue as the car will detect an excess power drain and may throw an "increased battery discharge" error.

fccs · 02-18-2015, 12:46 AM

Quote:

Originally Posted by jwzimm

There are several power buses in the car. Each is controlled by the CAS and relays. Very little receives a constant 12V supply to preserve battery life. Lots of control modules are powered off the bus that goes dark after about 30 minutes (referred to the car going to sleep). There is also a bus that provides constant 12V power unless the CAS detects the battery is draining beyond the point where the car can start.

Tapping the battery directly can be an issue as the car will detect an excess power drain and may throw an "increased battery discharge" error.

Then what the hell does everyone use for constant 12v? I'm planning to just go right to the battery to make it easier. Now I have to worry about a battery error if I do so? lol

Wongway · 02-18-2015, 10:25 AM

Quote:

Originally Posted by fccs

Then what the hell does everyone use for constant 12v?

The battery

Quote:

Originally Posted by fccs

I'm planning to just go right to the battery to make it easier.

best and most sure fire way, period. You'll spend more time figuring out which fuse is right rather than just running it to the battery as you're finding out first hand.

jwzimm · 02-18-2015, 10:47 AM

Quote:

Originally Posted by fccs

Then what the hell does everyone use for constant 12v? I'm planning to just go right to the battery to make it easier. Now I have to worry about a battery error if I do so? lol

Quote:

Originally Posted by Wongway

The battery

best and most sure fire way, period. You'll spend more time figuring out which fuse is right rather than just running it to the battery as you're finding out first hand.

Read this post: http://www.e90post.com/forums/showth...light=fuse+tap

Wongway · 02-18-2015, 12:50 PM

Quote:

Originally Posted by jwzimm

Read this post: http://www.e90post.com/forums/showth...light=fuse+tap

From another thread about installing a head unit awhile ago...

Quote:

Originally Posted by jeffb335

Yes, those who have followed these threads from the beginning will recall we had a BIG discussion already about the best way to wire constant power. Frankly your experience is EXACTLY why its probably a better idea to just run a wire to trunk and connect to the battery. You have now spent hours fiddling with the fuse box when it would have taken maybe 30 minutes +/- to run a wire to the trunk.

Get it done right the first time, there's no need for this to come up. 30 minutes vs how many days/hours of trying and failing? Not to mention, not all our fuse boxes are configured in the same manner as many prior E90 owners have found as well. I suppose then, that would require people to actually use the "search" function though...

jwzimm · 02-18-2015, 02:27 PM

Quote:

Originally Posted by Wongway

From another thread about installing a head unit awhile ago...

Get it done right the first time, there's no need for this to come up. 30 minutes vs how many days/hours of trying and failing? Not to mention, not all our fuse boxes are configured in the same manner as many prior E90 owners have found as well. I suppose then, that would require people to actually use the "search" function though...

That thread was more about educating people on the various power busses in the car.

"Doing it properly" is finding the appropriate relay bus to tap in the fusebox right next to the head unit, not chasing a power wire all the way to the trunk to connect to the battery. (btw, this wire would not be routed through the IBS at that point and could present a safety hazard in the event of an accident)

If you review the fuse diagrams you can find either a populated fuse for an accessory on the correct relay bus or one that it not used. A little research would allow him to find an appropriate fuse to tap and solve the problem.

02-13-2015, 10:21 PM	#1
fccs Private First Class 29 Rep 147 Posts Drives: M4 Join Date: Jan 2015 Location: Las Vegas iTrader: (0)	Time keeps resetting after aftermarket headunit? I installed a aftermarket double din headunit. Everything works great, steering wheel controls, sound, chime, everything. Except, if the car sits off for a while (30min-1hr) the time is reset everytime I get in and start the car. Any ideas?
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02-13-2015, 11:18 PM	#2
Wongway Captain 28 Rep 609 Posts Drives: 328i xdrive Join Date: Sep 2013 Location: Pittsburgh, PA iTrader: (0)	Yep... You either tapped the wrong fuse, and/or didn't bother running the constant power wire to the battery.
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02-14-2015, 12:42 AM	#3
bmw325i Major General 223 Rep 5,120 Posts Drives: 2006 BMW 325i Join Date: Oct 2010 Location: United States iTrader: (8)	+1 it is a problem with the constant 12 volt source.
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02-14-2015, 05:23 AM	#4
Socket Lieutenant General 4542 Rep 11,903 Posts Drives: 335i Join Date: Nov 2014 Location: Australia iTrader: (4) Garage List 2008 BMW E92 [0.00]	you need a flux capacitor Attached Images
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02-14-2015, 07:38 PM	#5
fccs Private First Class 29 Rep 147 Posts Drives: M4 Join Date: Jan 2015 Location: Las Vegas iTrader: (0)	Where do you tap into for a constant power wire? Thought there was one on the side under the door trim piece or whatever you call it
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02-15-2015, 09:49 AM	#7
fccs Private First Class 29 Rep 147 Posts Drives: M4 Join Date: Jan 2015 Location: Las Vegas iTrader: (0)	I tapped into the constant wire up front, I guess I gotta run it to battery lol
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02-15-2015, 10:02 AM	#8
Harry335i Second Lieutenant 5 Rep 200 Posts Drives: 2011 335i Join Date: Sep 2011 Location: Summerville iTrader: (0)	If you are confused with these answers, you probably should not be working on wiring up anything in a vehicle.
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02-15-2015, 11:00 AM	#9
ctuna Lieutenant General 1911 Rep 13,102 Posts Drives: 325xi 06 wagon MT Join Date: Jan 2010 Location: Santa Cruz, Ca iTrader: (0)	HU head unit http://www.e90post.com/forums/showth...ight=head+unit http://www.e90post.com/forums/showthread.php?t=1036190 http://www.e90post.com/forums/showth...hlight=dynavin http://www.janus-design.net/english/ http://www.e90post.com/forums/showthread.php?t=355089 http://www.e90post.com/forums/showth...ight=head+unit http://www.e90post.com/forums/showth...hlight=dynavin http://www.e90post.com/forums/showth...hlight=dynavin http://www.e90post.com/forums/showth...light=retrofit http://www.e90post.com/forums/showthread.php?t=993447 http://www.e90post.com/forums/showthread.php?t=1016187 http://www.e90post.com/forums/showth...hlight=dynavin
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02-16-2015, 11:55 AM	#12
mathematics Captain 69 Rep 994 Posts Drives: 08 328i e93 alpine white Join Date: May 2009 Location: Queens, NY iTrader: (0)	do you mean the instrument cluster time resets or the head-unit's time resets? __________________ iPhone 6 Plus (iTunes library/iTunes radio/Waze, etc) to Airport Express via AirPlay. Toslink out of Airport Express to Helix P-Six DSP. PHD AF 1.C tweeters, PHD FB 4.1 midranges. Jehnert Door Cards and mid-bass'.
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02-16-2015, 07:46 PM	#14
fccs Private First Class 29 Rep 147 Posts Drives: M4 Join Date: Jan 2015 Location: Las Vegas iTrader: (0)	Found out stock headunit goes into deep sleep mode, that's why the aftermarket doesn't work by using a 12v constant up front unless it's a fuse 12v or run directly to battery. Interesting
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02-17-2015, 04:16 AM	#15
Socket Lieutenant General 4542 Rep 11,903 Posts Drives: 335i Join Date: Nov 2014 Location: Australia iTrader: (4) Garage List 2008 BMW E92 [0.00]	. Attached Images
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02-17-2015, 11:36 AM	#17
jwzimm Colonel 687 Rep 2,770 Posts Drives: '16 M3 Join Date: Jun 2011 Location: Renton, WA iTrader: (17)	There are several power buses in the car. Each is controlled by the CAS and relays. Very little receives a constant 12V supply to preserve battery life. Lots of control modules are powered off the bus that goes dark after about 30 minutes (referred to the car going to sleep). There is also a bus that provides constant 12V power unless the CAS detects the battery is draining beyond the point where the car can start. Tapping the battery directly can be an issue as the car will detect an excess power drain and may throw an "increased battery discharge" error. __________________ 2008 Honda S2000 - Current 2016 F80 M3 - SOLD!! 2011 e92 X-Drive Coupe - SOLD!!
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