2008 G35X with 99K Mi. Audio died, screen went black. A/C stuck on auto . Controls not lit. Fuse #34 was blown, but replacing made no difference. Is this the circuit board issue mentioned before? Is the whole system shot? I don't trust myself to do any electronic work here. Seems like only a dealer fix and expensive. Anyone else has had to deal with this?

The A/C Amp on the '08 G35 is in exactly the same place as the Maxima, so you may have the same issue. We call it the "piggy bank". There's an open programming slot in the top of the Amp that's just big enough for a penny or dime to fit through, and it's directly beneath the ledge in front of the display. If a coin falls off the dash and through the ledge and hole, it shorts out stuff inside the amp. There's a lot of interconnected stuff, so the symptoms can be almost anything, even a CANbus crash. It's also possible your AV Unit simply went south, that's directly supplied by fuse 34 and all the display and key functions go through it. Besides the AV, fuse 34 supplies the Display, iPod Adaptor, Woofer, Camera Control Unit, CD Changer, Telephone Adaptor, and XM Tuner, so there's a pretty long list of suspects, but the AV is the only one that's central to all the functions that are down on your car.

Thanks for answering. I maybe don't quite follow you . Maybe this is differently configured or because of the CD changer. I did put another 15A in #34. No change other than the lights for the A/C controls showing.

smudge801 wrote: ↑

Sat Jun 12, 2021 12:30 pm

Maybe this is differently configured or because of the CD changer. I did put another 15A in #34.

Your car may or may not have all the stuff I listed, that was simply all the possibilities listed on the power diagrams. You'll definitely have an AC Amp and AV Unit, which are the two most likely culprits. The Amp will be stacked on top of the AV, both located directly behind the climate control panel. If you physically shake the Amp and it rattles, you probably have a dime in the piggy bank.

Well, turns out even the dealer can't get a replacement for this system. The service manager recommended going aftermarket. I hate to lose the OEM look with the screen. I did find an outfit called 1Factory Radio with refurbished head units and I'm having them check by VIN to make sure of compatibility. They have refurbished radio control panels as well. Those have the big circuit board on the back. I'm wondering if that's where the failure is rather than in the big chassis radio/CD player head unit. Wondering whether I should buy both or maybe just begin by replacing that control panel/board and see what happens. A youtube video looks as though its easy to access. Anyone have experience or thoughts?

The control panels don't go bad often except for worn-out encoders, and I don't actually think it's possible for a bad panel to crash the whole system. I think the same is true of the display, although you could try disconnecting it and see if other functions like the audio wake up. Same for the AC Amp, provided there's no penny in the piggy. Most likely it's the AV Unit that's dead.

So, you recommend ordering just the head unit if its deemed a compatible part number?

Yes, but if possible I'd try yanking the connectors on the two other components first, to make sure it's the right diagnosis. If the AV is the real culprit then disconnecting the AC Amp and display should make no difference. If anything changes when you disconnect, like the audio waking up or lights coming on, then the culprit is more likely the disconnected part.

Well, still baffled. We swapped out the AV unit with the 1Factoryradio refurbished one. No rattle in the a/c amp. Did all with the battery disconnected, so didn't try pulling cables on individual components. Buttoned it all up and got same result...fuse 34 immediately blew (visible arc). Display screen, climate controls and audio all dead. Don't know what else to try, having no real expertise here. 1Factory has reconditioned control panels. That big circuit board behind seems to have many components that could blow, but their guy also says its not likely the problem.

Is going for an aftermarket install a solution? If I have Best Buy do an install, is the JDM or Metra kit going to also restore the climate controls? Right now, its stuck on....vital in Texas, Will have to have control of it though. Since the dealer didn't want to look at this problem, I'm losing it over this.

If the fuse blows immediately and the culprit isn't a component on the circuit, then you have a short in the wiring. It isn't rocket science, but you need to eliminate devices first, unplug them one at a time and see if the fuse quits blowing. If you've gone through all the possible devices on the circuit and nothing changed, then you're chasing a wiring short. Throwing parts at it will avail you nothing, but an afternoon of systematic unplugging will avail you a lot. So will a simple short-finding tool. I did an extensive writeup on short diagnosis that you can find here:

the-problem-with-shorts-part-i-t628344.html
the-problem-with-shorts-part-ii-t628356.html
the-problem-with-shorts-part-iii-t628377.html

The reason most dealerships don't want jobs like that is because locating shorts is a tedious business and must be approached methodically. But with your own elbow grease, the WD's available on this site, and the methodology expressed in those writeups, you can definitely find it for yourself.

I really appreciate your advice and expertise. I'm getting some help and trying to hunt down the short. Nothing visible, but we'll be at it in another day or two. Fun in 100+ degrees.