I didn't want this info to be lost in my other thread about replacing the head unit in my 2010 Crew Cab with Rockford Fosgate system, but just wanted to throw some info out there for those of you that may be contemplating it. Before I started, I was searching high and low for these answers, and did not have definitive ones -- so I compiled some info thats easy to find. If a mod wants to sticky it, feel free.
First -- this is based upon replacing your head unit with one that only has a 2.5V preamp output. Many of you have replaced their units with 4.0V preamp units, and were happy with the results. In that instance, I believe it was sometimes necessary to either utilize a relay for the remote amp turn on, or to incorporate ground loop isolators to minimize popping that is heard when changing sources.
For 2.5V head units, you are faced with another issue. Crutchfield or other online stores that utilize Metra's database will always tell you to use the 70-7551 Metra interface for hooking up your new head unit to the factory system. This will work -- BUT -- you won't be happy -- especially if you were hoping to achieve at least the same level of audio you had with the factory head unit. The 2.5V output is at its peak, meaning full volume. The RF amp expects at a normal volume about 2V based upon the schematics in the Nissan service manual. At 50% volume, you're only going to be around 1.25V (assuming the voltage change is linear) -- and what you will end up with is the RF amp being fed by too low a level.
To correctly utilize a 2.5V system, you will have to give up on the prospect of using the RCA pre-amp outputs from the head unit. Instead, you will need to use the high-level speaker outputs that your new head unit has. You will also need to use a generally decent quality LOC (line output converter) to now step down the power from the head unit to something more sensible for the RF amp.
If you look at PAC, they make a couple of different units. The OEM-2 unit will achieve this, and based upon what I read, was a very good unit. However, it appears to have been discontinued and replaced with the SOEM-4. Let me save you time and money: DO NOT USE THE SOEM-4. It is a piece of junk. It is very poorly constructed, has terrible reviews on any site you look at, will introduce an annoying hiss to your speakers whenever it is on, is abnormally large (since the Fronty has a bit of room in the bottom part of the area under the radio pod, it will fit --- but you will need to carefully maneuver all of your harnesses to make it so.)
The SOEM-4 lasted just about 2 weeks in my truck.. I was not very pleased with it. So, the solution? Read below...
PAC also makes the ROEM-NIS2. This is a kit that uses the PAC OEM-1 LOC, and also provides the proper vehicle harness for our Frontiers. Yes, their application guide lists it as being used for a bunch of other Nissan and Infiniti systems with the Bose system. BUT, it performs exactly the same and WILL work with the Frontier RF system with NO MODIFICATIONS. The construction and quality of the OEM-1 used in the ROEM-NIS2 is superior to the SOEM-4. Its in a solid case, the electronics appear to be soldered well, and the components are not noisy. You will get a clean audio signal to your RF amp.
I found mine on Amazon for $29. Installation was a breeze. Simply connect one end of the unit to the two Nissan factory harnesses (Meaning you do NOT need the 70-7550 or 70-7551). On the other end, the OEM-1 has a 2nd harness that has speaker wire inputs. If you read the instructions, they specify TWO (+) for every (-). One (+) is the high level, the other (+) is the low level. DO NOT do what an Amazon reviewer said and tie the HIGH/LOW together. You only need to hook up the HIGH (+). The 4 LOW (+) wires you will tape up and not use. The rest of the wires are pass-through wires for the vehicle harness:
To your new stereo's constant 12V
To the stereo's 12V Accessory Input
To the stereo's illumination lead
To the remote amp turn-on lead of the stereo
To the ground lead on the stereo. I also took this lead and grounded to the chassis. I used one of the two screwholes that are left empty from the factory radio bracket once the Metra dash kit is installed
Tied up/Not Used:
Grey/Green/Purple/White leads that have RED stripes (these are the LOW (+) leads). Also, solid BLUE is not used (Power Antenna) -- you do not want to utilize the power antenna lead as an amp remote, since some head units only energize this when the FM radio is active. The Blue/White remote lead is active at all times.
For adjusting gains, this is a personal preference -- But I found that adjusting the head unit to 75% and adjusting the gains to the point where there was no distortion was perfect. Turned completely to the left, the arrow on the gain pots points to about the 11:00 position. Setting them to about 12:00 was perfect. Out of the box, they were set to about 3:00 which was too high. The max they go to is about the 7:00 position.
I hope that helps anyone that may have been searching for definitive answers on this.
This is the ROEM-NIS2:
INFORMATION FOR ASWC AND NISSAN BLUETOOTH BYPASS:
If you are using the Axxess ASWC steering wheel interface, and your Frontier was originally equipped with Bluetooth controls, you will need to bypass the Nissan bluetooth module under the passenger seat in order to use the two phone buttons on the steering wheel. To do so, gain access to the bluetooth module under the seat -- it is easier if you can remove the seat, but I was able to do it by just pushing the passenger seat all the way forward and working on the harness from the back seat.
Metra Document on Bluetooth Bypass: http://contentdocs.installernet.com/documents/vehicle/12144.pdf
At the bluetooth control unit under the passenger seat -- the unit is the smaller unit closest to the door. On the harness, I ended up cutting the 6 wires needed for the bypass:
Pins 12 (Brown) & 17 (Violet) -- Connect together
Pins 13 (Blue) & 18 (Light Green) - Connect together
Pins 14 (Green) & 19 (Orange) - Connect together
Then on the 16-pin connector that previously plugged into your factory stereo (this will end up unplugged and not used with an aftermarket stereo), I did the following:
Black wire of ASWC to GROUND.
Red wire of ASWC to a 12V ACC wire (RED, if you are using the Metra harness)
Grey/Red wire of ASWC to VIOLET on Nissan 16-pin harness
White/Green wire of ASWC to LIGHT GREEN on Nissan 16-pin harness
Finally -- the ORANGE wire in the Nissan 16-pin harness gets connected to GROUND.
If you are curious what these wires are, the service manual says this:
- Pin 12 (Steering switch signal A INPUT) bridged to Pin 17 (Steering switch signal A OUTPUT)
- Pin 13 (Steering switch signal B INPUT) bridged to Pin 18 (Steering switch signal B OUTPUT)
- Pin 14 (Negative for both Signal A & B Input) bridged to Pin 19 (Negative for both Signal A & B Output)
If you go this route, make sure you unpair any phones from the Nissan system, and turn off the bluetooth, before bypassing the controls. The bluetooth module feeds the audio system in the RF system, and without steering wheel controls, if they are still paired/on, if you get a call and the Nissan system pairs up with your cell - you'll have no way of answering it.
ASWC Known Issues & Fixes
Unfortunately ASWC units that shipped with firmware prior to Feb 2012 have a bug where the ASWC will randomly change the source on the radio. The fix is to update the firmware to at least Version 3.06. The downside is, I dont believe there is any indication on the box or unit to determine which version is installed. There are 4 routes you can take to fix this:
1) You can send the unit to me and pay for shipping and $5.15 return shipping and I'll be happy to update for you. See http://www.clubfrontier.org/forums/f24/free-aswc-firmware-upgrades-79135/
for more info
2) Purchase Metra's official firmware updater cable for appx $40 and update the firmware yourself
3) Go to a local stereo shop and see if they will update the unit for you.. They will likely charge you, especiallly if you didn't purchase from them.
4) Purchase the cable LAFrontier mentions here for appx $5 and update the firmware yourself: http://www.clubfrontier.org/forums/...ve-metra-usb-cab-programming-cable-5-a-79367/
-- this may or may not work because the Metra updater app may not recognize the proper hardware ID for the cable - YMMV. The updater expects a cable with VID_0403 and PID_6001 (Vendor ID 0403 is Future Technology Devices International - FTDI)
The official cable that Metra sells is actually FTDI Model TTL-232R-5V-WE and can be found around the web for as low as $18 in its "non-Metra OEM" form -- but the "WE" designation in the part number indicates "Wire Ends", meaning you will also need to attach a connector to the bare wires.