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AznRurouni007
07-09-2006, 06:28 PM
I just got a new head unit, the Kenwood KDC-MP4032, installed it .. works fine, except for when I turn the key off, it forgets all my presets, settings, etc ... which screams that the constant 12v power isn't working, but i tried all three constant 12v hardwires, and even directly wiring it to the positive battery terminal, but it still does the same thing .. does anybody know how to fix this, or is it just a defective stereo?

Good thing I bought it from crutchfield, shipping me a brand new unit next day air :p

shootme5150
07-09-2006, 08:27 PM
silly question... but are you sure you don't have the two wires swapped? Yellow goes to constant, red to acc. Got a DMM? Shut the ignition off and check to see if you still have 12V / ground. If so, sounds like a defective unit.

AznRurouni007
07-09-2006, 09:57 PM
Yeah, its the yellow wire i'm connecting for the constant 12v. I have a DMM, and tried measuring the constant 12v's i do have, they measure anywhere from 0.00-4.32, which is strange because they work to power my stereo, they just don't stay on when I turn my car's ignition off. It seems like strange problem for a brand new unit *shrug*

shootme5150
07-10-2006, 01:09 AM
wait... ALL of your constant 12V wires measure <5V??? What does your battery measure? The problem isn't your HU... if you're measuring that low, you've got a problem before the HU. You're not dropping 8-12V through your HU without it exploding in a blaze of glory.

AznRurouni007
07-10-2006, 02:29 AM
Ok, i went out and retested with the DMM, the battery measures 0.12-0.14 when set at ac, maximum of 20v to be measured.

The two "constant 12v input" wires measure 0.00 or 0.01 when the key is off, when the key is on they measure all over the board from 0.00 to 4ish, but they power the radio correctly except for the loss of memory.

The one "constant 12v to radio" measures at 0.00 to 0.01 whether the key is on or off

The part that really gets me is, i wired my HU right to the + battery terminal to test it, and the unit still lost power when the key was turned off

Hope that makes a little more sense, thanks for your help!

jack_13
07-10-2006, 03:03 AM
battery? should it be reading those sorts of numbers???

splboy_13b
07-10-2006, 03:31 AM
the battery measures 0.12-0.14 when set at ac


last time I checked batteries were DC

If there was a reason for using AC I'd like to know (I'm not extremely experienced with multimeters)

saiyaneye
07-10-2006, 03:45 AM
Did you figure this out yet?

shootme5150
07-10-2006, 10:47 AM
check it with DC and let me know the results.

AznRurouni007
07-10-2006, 05:34 PM
Ok awesome, that worked (DC setting).

With the key off
----------------
The battery positive terminal measured 12.46
The two "constant 12v input" wires measured 12.25
the one "constant 12v to radio" wire measured 0.00 to -0.03

With the key on
----------------
The battery positive terminal measured 11.65
The two "constant 12v input" wires measured 10.80-11.50, hovering mostly around 10.98-11.05
the one "constant 12v to radio" wire measured 0.00 to -0.03

Vestax05pro
07-10-2006, 05:39 PM
One way to test to see if it's the HU that has problems is to wire both ignition (red) and constant (yellow) to a constant/battery connection. If it doesn't save its setting, then you have an HU problem. Otherwise, double check your connections again. BTW, what car is this?

shootme5150
07-10-2006, 05:39 PM
do you have anything connected to the "constant 12V to radio" wire? What wire is your yellow wire hooked up to right now?

AznRurouni007
07-10-2006, 07:05 PM
One way to test to see if it's the HU that has problems is to wire both ignition (red) and constant (yellow) to a constant/battery connection. If it doesn't save its setting, then you have an HU problem. Otherwise, double check your connections again. BTW, what car is this?

I wired both acc. and constant to the battery, and it keeps its settings, but as is expected, it stays turned on when the key is not in the ignition; on standby it'll drain the battery if i keep it wired this way normally

Next I wired power from the battery to the constant 12v and the acc. 12v, powered on ok, saved preset ok, this time I kept the constant 12v connected, and disconnected/reconnected the acc. 12v, and it lost the presets, wth is going on?

Vestax05pro
07-10-2006, 07:12 PM
I wired both acc. and constant to the battery, and it keeps its settings, but as is expected, it stays turned on when the key is not in the ignition; on standby it'll drain the battery if i keep it wired this way normally

Next I wired power from the battery to the constant 12v and the acc. 12v, powered on ok, saved preset ok, this time I kept the constant 12v connected, and disconnected/reconnected the acc. 12v, and it lost the presets, wth is going on?

Have you tried putting your yellow constant wire on acc and red on constant? Your harness is probably reversed.

In a properly installed HU without any problems, leaving constant on 12 volt acc input, then 12v switched on a constant input, would allow the unit to turn on but not save settings. This is what I see happening according to the way you described it. Again what car is this?

shootme5150
07-10-2006, 10:04 PM
Have you tried putting your yellow constant wire on acc and red on constant? Your harness is probably reversed.

thmbup thmbup thmbup You beat me to it :(

If this is the case, make sure the red wire is fused... typically the yellow is. If the red isn't, fuse that bytch.

AznRurouni007
07-10-2006, 11:39 PM
That did the trick, you guys rockk .. thanks for all your help and I'll be sure to do the same once I get some more experience under my belt.

hey shootme, what does "fused" mean?

If anyone still cares, I drive a 1995 toyota avalon hehe, sorry I forgot to answer it above

shootme5150
07-11-2006, 12:23 AM
That did the trick, you guys rockk .. thanks for all your help and I'll be sure to do the same once I get some more experience under my belt.

hey shootme, what does "fused" mean?

If anyone still cares, I drive a 1995 toyota avalon hehe, sorry I forgot to answer it above
Your yellow wire should have a fuse inline with it. Your red wire needs to have the same to protect you from big, bad fires.