constant wire, memory, impossible problem
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=126733
Printed Date: July 07, 2025 at 5:17 PM
Topic: constant wire, memory, impossible problem
Posted By: volvo850
Subject: constant wire, memory, impossible problem
Date Posted: March 26, 2011 at 8:08 PM
Hello, I have been wiring my own stereos for 12 years. This is a problem I have never encountered.
I own a Volvo 850 - 1995
I have everything wired correctly, I tested the constant 12V wire in the harness and it is good, fuses are all good, inline fuse in the stereo's 12V constant is all good.
I get power, and it turns off and on with the ignition.
Upon restarting, it has lost all memory as if the constant and igntion are swapped. But they are not.
I heard that Volvo's may have this flaw as the factory stereos would only get power from that wire when the ignition is switched over...in which case every time I power down it loses the connection to the battery?
I am absolutely pulling my hair out and am hoping someone out there knows what the hell is going on...
Thanks.
-Vinny
Replies:
Posted By: i am an idiot
Date Posted: March 26, 2011 at 9:56 PM
What kind of radio is it? Have you tried to run wires directly to the battery to see if there is a problem with the cars wiring?
Posted By: volvo850
Date Posted: March 27, 2011 at 10:09 AM
i am an idiot wrote:
What kind of radio is it? Have you tried to run wires directly to the battery to see if there is a problem with the cars wiring?
Ya I have, and it works fine now and worked fine on my previous car.
It's an ALPINE CDA-9813. 20A Inline fuse circuit
Posted By: volvo850
Date Posted: March 27, 2011 at 10:10 AM
Would a pinched wire somewhere along the way cause this? No...right?
Posted By: DYohn
Date Posted: March 27, 2011 at 11:00 AM
Do you have +12V on the constant power wire with the vehicle turned off and no key in the ignition? If you do, then there is likely a defect or possibly a blown fuse inside the head unit itself. ------------- Support the12volt.com
Posted By: volvo850
Date Posted: March 27, 2011 at 1:41 PM
So it turns out that although I thought I had tested the 12V constant, I guess I must have messed up.
The whole time I had thought the problem was the 12V and the ignition wires were mixed and it turns out I was right.
In a Volvo, the 12V constant is a RED wire, and the ignition is a YELLOW wire. Completely backwards from Japanese cars and the Japanese head unit I own. So the yellow wire out of my inline fuse box goes right into a red wire...seems insane.
Thanks for the help, guys.
-Vinny
Posted By: DYohn
Date Posted: March 27, 2011 at 4:31 PM
volvo850 wrote:
So it turns out that although I thought I had tested the 12V constant, I guess I must have messed up.
The whole time I had thought the problem was the 12V and the ignition wires were mixed and it turns out I was right.
In a Volvo, the 12V constant is a RED wire, and the ignition is a YELLOW wire. Completely backwards from Japanese cars and the Japanese head unit I own. So the yellow wire out of my inline fuse box goes right into a red wire...seems insane.
Thanks for the help, guys.
-Vinny
Glad you figured it out. A lesson for all installers: even if you've been doing it for years and know the standard color codes like the back of your hand, there's no substitute for metering.  ------------- Support the12volt.com
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