Factory HU / Wired FM Mod / wiring

[DadeM]

Hi everyone, I got a wired FM modulator to add an aux to my factory HU (price was the driving factor at the moment, a new HU will be the answer later..). I followed the guide here for removing the HU, etc and that went fine. I tapped into the HU wires for Acc power and ground for the modulator. Now the modulator powers up fine (there's a lighted switch) but the HU is totally dead. The clock doesn't come on, etc. I thought initially that there was just a wire loose in the plug to the HU, but when I turned on my headlights today, the HU lit up the buttons and CD guide light, but not the display. So my question is, does the HU "know" that I removed it and messed with its wires or is there still the chance that something is loose? (I disconnected the battery when doing this of course)

BTW, for anyone reading that might do the same, there's a huge "natural" space between the floorboard and dash assembly (driver's side) that's great for running the wires and keeping them hidden.

Thanks!

[Promise Land]

The headunit doesn't know that you did anything other than removed the power from it. It should have just lost the memory settings for the station presets and the clock. Whatever you tied into for power is draining too much power away from the radio (and the lights give some of it back somehow).

Do you remember the color of the wire you tapped into?

This came up with a Google search:

2007 Nissan Versa Car Stereo Radio Wiring Diagram

Radio Constant 12V+ Wire: Brownish Orange (Thickest Wire)Radio Switched 12V+ Wire: CyanRadio Ground Wire: BlackRadio Illumination Wire: OrangeRadio Dimmer Wire: n/aLeft Front Speaker Wire (+): WhiteLeft Front Speaker Wire (-): Brown/PinkRight Front Speaker Wire (+): GreenRight Front Speaker Wire (-): Red/BlueLeft Rear Speaker Wire (+): RedLeft Rear Speaker Wire (-): PurpleRight Rear Speaker Wire (+): TealRight Rear Speaker Wire (-): Gray

[DadeM]

Oh, sorry I forgot to mention, I got a copy of the service manual and looked up the wire config. I tapped into the light green and brown that were listed as acc power and ground respectively. I verified that it's only getting power when the key is in acc mode too, so I think that's right. I never thought about it taking power away from the HU, but would it do that even when turned off? Thanks for the reply!

Edit: If this is indeed the case, any ideas where to get some power from back there? It doesn't have to be ACC because the thing itself has a switch I suppose.

[Promise Land]

It sounds like the problem materialized because of the unit. Another place you could pull a switched power and ground is from the 12V power point in the center console.

[DadeM]

Hm strange. I got bored enough to try something else, and I unplugged the FM mod and the problem is still there. (Wires still attached, but it disconnects from the mod itself) So it doesn't look like it's eating the power. I'll have to check the wire hood I guess and see if something's loose. The problem is that the connectors are so tiny, I can't fit the leads from my multimeter in there. D: I thought about power from the console, but it's SO far from the back of the stereo, and I didn't want wires all over the place. Thanks though!

[jangelj]

i put in a wired fm modulator in my 09 V. works fine. biggest problem was the antenna adapters.

i also tapped into the radio plug for power. used a random screw behind the radio for ground. no problems. If you want to find an alternate power source, get an add-a-fuse. plugs into a circuit on the fuse panel and adds a circuit. works great.

good luck. sounds to me like to have something shorted somewhere. i know that doesn't help, but you may want to remove everything you have done, make sure the radio works, then start again.

[DadeM]

Thanks for the response jangelj, that does help knowing that someone else got it to work. I tried what you suggested and removed everything, still no joy. So I used the multimeter to test where the leads from the wiring hood attach to the PCB and it is getting all 12V of power, so the only thing I can think is that the HU somehow broke or does have some kind of "stolen" mode that it went in to. Either way, looks like it's a new HU for me. Can't have no music in the car! Thanks for the help guys.

EDIT: I'm a total idiot, it was the fuse. Note to anyone that comes along. If the "audio" fuse blows (under the good) the dimmer and aux lines to the stereo still work! x_x
Modified by DadeM at 10:40 AM 2/10/2010