Screwed up tail lights after installing aftermarket radio in 2006 Altima



Hi guys, love listening to the show every time we’re on the road. Never thought I’d have something entertaining enough to post about, but after working on my fiance’s car I screwed it up enough to need some professional help. so here goes…

this is a 2006 altima, non bose radio. For christmas i decided to put in an aftermarket JVC since she’s on the road all the time. The initial installation went fine, everything worked except for the steering wheel controls, which needed an extra module. After this initial installation we even tested the headlight switch to make sure the headunit dimmed correctly.

When the steering module (PAC SWI-JACKv1) arrived in the mail a week later, i took things apart again and this time had to strip some wires from the wiring harness and solder some resistors. After plugging everything back together that night the steering controls worked great, but we noticed the dashboard lights not dimming - they’re on full bright all the time, the dim switch doesn’t do anything. Also the A/C backlights don’t come on anymore so we fumble in the dark for any temp changes. Lastly, someone waved us down two nights ago and pointed out to us that BOTH of our tail lights dont come on when we turn on the headlights - though the brake lights work.

So it looks like a central problem - I’ve checked both fuses under the dash and next to the battery, but everything looks clean. Any suggestions besides taking it to the dealer for hundreds of dollars of diagnostics?

Needless to say I’ve a very patient and understanding fiance, but i’m pushing my luck here!

thanks for any help everyone!


The lights in the head unit are probably supposed to be connected to the panel light circuit, which varies from 0 to 14 volts depending on where the dimmer is set.

Did it need a resistor in that circuit to bring the light level down? Just curious.

As far as the AC backlights, you may have inadvertently installed a resistor in series with them.

It could be possible that you crossed the dimmer with the parking lights. This would explain why the dash lights are on 100% whenever the parking lights or headlights are on (I am assuming that part… is that correct?).

Now if the parking lights are on the dimmer circuit, you may see them come on when you fiddle with the dimmer. Maybe not. The load of the parking lights is far larger than the dash lights and probably would burn the dimmer up.

Unfortunately it is impossible to tell what has happened without seeing, and more importantly, measuring voltage and current readings. It is very important to retrace everything you have done… exactly. Obviously, something went wrong.

This could get to be a very involved thread… it’s up to you.


When installing after market sound systems there always seems to be a pair of wires left over when all the others are matched and the installer assumes that those 2 wires must be conected. After connecting the 2 leftover wires something fails and that last connection isn’t considered for quite some time. Often the radio has 2 ground wires with one left unconnected and the harness adapter has a wire for the dash lights which comes through the dimmer. Connecting these two usually kills the dash lights. But, it would be advisable to take a fresh look at the adapter harness and the car’s wiring diagram and compare the proper pairing of all wires. Short to ground, short to power and feedback from lack of ground can occur. And diagnosing and repairing electrical circuits can be a real pain.


the part that makes me suspect circuit board damage is because i’ve attempted to completely uninstall the aftermarket unit - removed the aftermarket harness, cut off the resistors, and plugged the original radio back in… still no dimming, and no tail lights.

to recap though, after i originally installed just the radio, dimming worked without problems. the factory harness is comprised of three plugs, two for the radio and one that controls steering wheel. those are the wires i spliced… never went into dashboard. And when i installed the aftermarket harness, there WERE a couple of wires hanging out, i just left them alone.

troubleshooting wiring IS a huge pain. have i eliminated shorting mistakes by returning everything to factory install? i guess what i’m hunting?for is a module somewhere that i can pin as the culprit and bring to dealer to replace… rather than have them charge by the hour to check each wire with a voltmeter - am


The more a mechanic knows the faster he can diagnose and repair the problem. And a mechanic familiar with diagnosing electrical problems may be able to use a wiring diagram and knowledge of your effort to install the radio to determine the faulty circuit before he sees the car.