So as part of a stereo upgrade I turned my attention to the radio harness wiring. previous owner had installed an Alpine aftermarket head unit., Excluding the tweeter/speaker wires which have been put aside in the photos, I am left with BLACK: Obviously ground GREY/RED Constant 12V power Small Red Antenna Power Big Red Switched power.. The only issue with this is that the switched power wire does not run in the radio harness, rather it is an add on.. It has taken power (tapped) from a plug directly behind the main dash, and has an inline fuse. None of which are OEM factory. So the question then begs as to how how does it work from the factory..? Where does the switched power come from to feed the OEM F355 Radio..? and does it run in the OEM radio wiring harness..? Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
I can't say for sure they were all wired the same from the factory but my '96 has no switched power wire in the radio harness. It only has the constant power wire so my radio is always powered.
All the wiring diagrams (2.7 and 5.2) show a very simple harness with 7 wires with no switched power. They don't show the interface with the Sony installation. The Sony has a 10 wire plug, various audio plugs and a CD Changer Bus plug). They must run a switched wire separately for a full stereo installation. Do you have to turn it off when you leave the car?
I had a closer look at the Stereo switched power red fuse and fuse holder. When I compared it to a fuse pulled from the ABS module, I discovered the red fuse is actually OEM.., as it has the same markings on it. Furthermore I also found some crumbly pink matter on the floor when I reached in to grab the fuse.. it appears to be the rubber weather seal for the fuse holder, that has gone rock hard with age.. I am realy confused now.. It appears the fuse and possibly the fuse holder are OEM..?!?! But it was spliced into the main harness so it can be its original position.? Does anyone else have a similar fuse/fuse holder under their dash or anywhere else in the vehicle..? Thanks in advance.. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
The "fuse holder" for the red fuse is actually a connector (having two female spade terminals) that somebody used as an improvised fuse holder. The fuses at the ABS could have been replaced at some point by fuses of the same brand as the one for the rafdio.
Yes thanks that makes sense.. What I think happened is that the stereo installer "borrowed" a free Red 10A fuse from the vehicle somewhere to make an improvised fused connection for the radio by tapping into the Blue thick accessory power wire in the white connector.. Sorry but for a professional installer that's pretty bloody bodgey.. Worse still is that he didn't even respect that beautiful Italian wiring harness by using an ISO-plug.. Instead he just chopped the radio plug off .!!. Now I am in a pickle.. Does anyone know of a place in the vehicle where I can borrow switched power from to feed to the aftermarket head unit without splicing or tapping further in to the wiring harness..? A wiring diagram for a 5.2 spyder would be of great assistance if anyone has one.. Thanks in advance..
The only way to do that would be to use a fuse tap. Ferrari doesn't use handy terminal strips (other than for live battery power) https://www.jaycar.com.au/double-standard-blade-fuse-socket-wire-tap/p/SF5115? Hopefully you could squeeze one of those under the relay panel cover. On a 5.2, switched power is found on passenger footwell panel fuses: 24 Aircon system, Instruments 25 Turn/reverse lights, cigarette lighter (on later cars), mirror heat, mirror control 26 Windscreen Wiper, brake lights, HVAC ECU 25 and 26 are depowered during engine cranking.
Besides the switched 12V + ACC power input, I also need an illumination wire to go into the head unit. My Instrument cluster is out getting sticky fixed ATM and I'm scared to turn the key position to ACC/ ON to test the wires involved in illumination , just in case I blow the airbag unit $$ So if anyone knows a good place to rob some power from when the parkers or headlights are activated please let me know.
On the OEM radio, don't the radio buttons and displays illuminate whenever you have key power? I can't recall if they are dimmable. Anyway, there are no handy fuses in the cabin which are energised when the lights are turned on. Light power does go through the footwell relay panel, but not through a fuse. I'm sure you don't want to run a wire from a frunk relay panel fuse. If your instrument cluster is not present, don't turn on the ignition. You won't blow the airbag, but you will latch an airbag fault light (simply because the Airbag ECU can't detect the airbag fault light circuit). A Ferrari SD1 tool is required for resetting the light.
Thanks for the input Qavion. When I got the vehicle there was no OEM Radio just aftermarket so I know nothing about dimmer capabilities of the OEM unit. Perhaps someone else can chime in and inform us regarding this..? I'm trying to hook up a Sony RSX GS9 to my OEM wiring harness. Got most of it sorted out but I am a little confused as what to do with the small red aerial amplifier wire in the OEM radio wiring harness....? With the old alpine unit it was easy as the Alpine plug has separate wires for the Pre-Amp Output (Blue/white) and the power antenna booster (blue) in the headunit rear input plug. The problem is that the Sony RSX GS9 does not have separate outputs for these.. It only has a single wire to perform both functions..(Blue/white #4) Is it safe to connect both the antenna booster ) and the amp remote switch on wires to this (Blue/white #4) on the sony headunit..? I've never encountered this before with a headunit install, and given the price of a NOS Sony RSX GS9 .. I realy don't want to take a risk with this.. Is anyone able to help..? Image Unavailable, Please Login Image Unavailable, Please Login
Sorry, no idea. Do you have an optional power amplifier with an "Amp Remote" in and what is it supposed to do? I assume the OEM antenna pre amplifier needs power. Does the "Amp Remote" also need power at certain times? I don't know if the OEM Sony head unit provides power to the antenna pre amp at all times or just when radio is selected.
To those who are interested..This is the explanation I got from a professional installer.. Yes it’s safe, the reason they do this is because that unit possibly has RDS. In order for RDS to work while on other sources other than radio, it still needs power during USB playback or Bluetooth streaming.So they use the remote turn on trigger, as that’s powered during all sources.. So moving on to my next question.. As I am unable to turn on my ignition I am wondering if anyone could tell me what these plugs behind the main instrument cluster are for.. The smaller plug was not connected to anything and freely swimming around behind the dash.. The larger plug was previously tapped for ACC power during the previous head unit install by tapping the fat blue/black wire.. But im looking for an easier solution.. Is the big red "looped" wire in this large white plug constant or switched power.. ? It has no wire on the other end..( see black zip tie in photo) and would be an easy clean solution to my problem if it was indeed switched power.. Thanks in advance.. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Still a bit stuck in terms of wiring this stereo. The Red wire to the headunit requires ACC Power.. However when I look at the installation instructions it says the following "If there is no accessory position, connect (the Red wire) to the +12 V power (battery) terminal which is energized at all times". In the f355 Radio wiring harness this is the Grey/Red Stripe wire.. What would be the effect of wiring the Red wire to constant 12V+..? Would this produce a constant current drain on the vehicles battery..? And if this is the case how does wiring the Redw ire to ACC prevent this..?
The Red wire is there just to enable automatic radio switch "on" and "off" with the ignition key. It can either be connected to ACC (in which case, when parked, you can listen to the radio without having to turn the ignition to "on") or it can be connected to ignition switched +12V. If the Red wire is connected to permanent +12V, you will not have the automatic radio switch "on" and "off" with the ignition key but you will have to switch it manually. There will be no additional battery drain in this case (provided you don't forget to swith the radio off before leaving the car). When the Red wire is connected to ACC, the radio will be switched "off" when the ignition key is turned to "off" (when there is no power in the ACC line). Radios with Yellow and Red wires for power supply: the Yellow wire is connected to permanent +12V and it is for the main power supply to the radio (carries high current); the Red wire carries low current and it is the "trigger wire" to switch the supply to the radio through the Yellow wire on and off; the Red wire, before going to the power switching circuit, goes to the radio's manual switch so, if the manual switch is "off" the power on the Red wire will do nothing; with the manual switch in "on" state, power/no power on the Red wire will switch the radio on/off.
