Clarion HU shuts off when lights turn on

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=11006
Printed Date: July 26, 2025 at 5:40 PM

Topic: Clarion HU shuts off when lights turn on

Posted By: beerstud136
Subject: Clarion HU shuts off when lights turn on
Date Posted: March 16, 2003 at 10:55 PM

1987 volkswagon jetta, clarion dxz835mp... first thing that i found odd was the fact that this car only ran 1 more wire, the intire electrical system is switched posted_image

but whatever i figured it out, install went fine and finished with out a problem, but then the girl tells me tonight that when she turns on her headlights her deck completely shuts off... a few things crossed my mind, but im still confussed, help!

Replies:

Posted By: esmith69
Date Posted: March 17, 2003 at 9:03 AM

Does it do this only when the car is turned off? Might wanna try checking the +12v constant going to radio for voltage, with the lights on and then with them off. If the voltage drops way down when you turn the lights on then that's prolly why the head unit turns off--it's got one of those under-voltage protection circuits.

Does the radio come back on once the lights are turned off? And are there any fuses blown anywhere (radio fuse, vehicle fuse, etc.)

When you wired the head unit, did you connect any of its dimmer/illumination wires up to the vehicle?

Posted By: beerstud136
Date Posted: March 17, 2003 at 2:31 PM

if she turns the lights off the hu comes back on, no fuses are blown anywhere and there were no dimmer/illumination wires hooked up, could this possibly be the problem, perhaps one of the illumination wires need to be hooked up to supply 12v+ when the lights are on?? i have no idea, first time ive ever touch a VW thanks

Posted By: beerstud136
Date Posted: March 17, 2003 at 2:54 PM

ok forget what i just said
ill explain again,
this car has a constant 12v+ source, and NO switched 12v+ source, so even though i know its not right, i just wired the constant and acc wires from the head unit toghter with the cars constant, it still shuts off when the car is off and keeps its memory, which is wierd? but when she turns on the head lights, the deck shuts off. whered the power go??? im so lost here, everything is wired properly, only there i did not wire the illumiation wire, and there is no dimmer in this car
https://www.the12volt.com/installbay/detail.asp?info=alarm&year=1985-92&make=Volkswagen&model=Jetta&ID=19113&type=Stereo

Posted By: lagatbezan
Date Posted: March 17, 2003 at 10:34 PM

try changeing your ground for the radio!! also, get a test light and test to see if you are getting power when the lights come on,same for the ground. my guess is that the ground is connected to the lights. don't ask me how, but i have ran into the same problem, just not in a vw. let me know what happens.

Ryan.

Posted By: beerstud136
Date Posted: March 18, 2003 at 10:58 AM

logical i guess, makes sense. just try running a new ground? see, this is why i have imports. why can't they just wire thier vehicles like a chevy, it's so simple!

Posted By: thepencil
Date Posted: March 18, 2003 at 1:09 PM

beerstud136,

I share the same opion as esmith69. From experience I know the radio unit shut off when there is a drop in votage. If that is the case with the head light going on and the radio going off, save yourself the headach. Run a seperate power wire from the battery to the radio and fuse it. You can run the power wire through the firewall on the driver side middle left coner. It's pretty easy to get the power wire through this VW, but do the test for power and ground first. This takes two minute, running the power through takes ten minute.

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Be careful whose advice you buy, but be patient with those who supply it. posted_image

Posted By: beerstud136
Date Posted: March 18, 2003 at 2:43 PM

thanks guys

Posted By: beerstud136
Date Posted: March 18, 2003 at 2:44 PM

but the same is only 1 wire power supply, there is no constant power it's all switched, if i run a direct line form the battery, how is the deck ever going to shut off?

Posted By: thepencil
Date Posted: March 18, 2003 at 9:48 PM

No ignition at all, try a toggle switched so you that can turn it off or on.

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Be careful whose advice you buy, but be patient with those who supply it. posted_image

Posted By: dragonrage
Date Posted: March 18, 2003 at 9:55 PM

If you want to avoid directly using the stock electrical system, use a relay. Put the stock power lead/ground across the coil, put a small capacitor in parallel with it to help prevent short dropouts if you want. And put (one of) the switch(es) to the switched power input. Relays won't be as affected by voltage drops unless it's a REALLY bad drop.

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2009 Pontiac G8 in planning stage
HU: ?
Speakers: ?
Amps: ?