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Discussion Starter #1
I've purchased an aftermarket double din stereo to put in my 2018 500e and I've got some questions. So first off, I'm aware it would probably be easier and faster to order a wiring harness. That's no fun. I bought this to tinker with and save on tolls. I work with electronics all the time so I'm not afraid of some wire splicing and can always re-crimp the wires and put them back in the header.

Now that being said, it's hard to do this without much documentation. Right now I'm just trying to get basic functionality going. Power to the unit and music through the speakers. I'll figure out the rest later. I have two main questions for the moment.

My head unit has a 12+, VCC and a GND wire.

Vcc is the remote power wire. It needs to connect with 12+ to turn the unit on. However, if I short them, the unit doesn't ever turn off... I'm guessing there's always power to the head unit? I see there's a "Radio On" wire which I figured was the remote switch for the stock one. But when I tapped my VCC to that wire, my aftermarket unit doesn't turn on when I put a key in the ignition as I expected... Is there a different wire I should connect my remote power wire to or did I just not sit long enough for the power to be killed to the main + and gnd going to the head unit?

My second question, my head unit has 4x 45w speaker outputs as well as RCA. If I'm tapping into the wires from the stock head unit, should I be using the 45w powered lines or the RCA? I'm not sure with this stock amp in the back. I don't want to fry it by sending power into line level input.

Should be a fun project. I'll start a progress thread on here soon.
 

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Discussion Starter #2 (Edited)
So upon further tinkering I discovered the "Radio On" wire appears to be the remote switch for the amp in the back. I have the speakers spliced in and working. I'm just missing however to have the unit turn off with the rest of the car.

Edit:
Also, it technically output sound but I'm not convinced with the head unit having an amp and the amp unit in the back that any long use this way will damage it. Can anyone confirm?

If that is the case, should I bypass the amp in the back somehow?


Edit 2:
I'm starting to get the impression I'm going to need a CAN BUS decoder to do basically anything. Even getting the unit to power on with the vehicle, unless I tap a 12v+ from something else in the car that only turns on when the key is in... Kinda janky way of doing it though.

Eventually, I'd love to get the steering wheel controls, back up camera (with guide lines if possible), XM, gps, mic, aux, and USB all hooked back up to my aftermarket unit.

Edit 3:
Figured I'd just keep updating this as I discover more if anyone else is going down a similar path.

I believe I am going to buy a Meistro RR2. It seems like it will solve all of my functional issues. From what I gather, it will read the CAN bus and then output various things to aftermarket units. I'm still worried about the amp in the back though and if I should bypass it or if it can take speaker level input.
 

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I have an RR in my 2018 500e. It gets you audio, steering wheel controls, backup camera with active lines, retained accessory power.

Do not expect OBD-II or most CAN features to work. For example, reverse trigger needs to be tapped. Plugging in OBD-II connector throws errors. Just keep it simple and it should mostly work. iDatalink has little interest in fixing 500e support since it differs from ICE version in certain areas.
 

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For your outputs use RCA since it’s going to the amp. Also make sure the amp turn on is still triggered. I had a few issues with audio but once I figured it out it sounds great.
 

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This was my very first head unit project. Happy to answer as much as I can, but I am no expert. The high level overview with iDatalink (Maestro RR, RR2, etc) is that they support 500's except the "e". Due to it being a low volume compliance car and them being based in Canada supporting our vehicle was never a priority. As I understand it Bosch did quite a bit of work on the system which resulted in differences between the ICE and electric versions. I think the RR is the only kit that includes back up camera retention, but there may be other kits that are cheaper or may work better if that isn't important to you.

I have no idea where any one signal comes from. I suspect some are direct wired when others may well be on CAN. When we get lucky it just so happens to be the same signal as the ICE version. I started with the RR and never tried a manual pin out.

Here is what I did to get the RR working in my 2018 500e with an Alpine ILX-F309:
  • Get all the Maestro hardware, harnesses, and adapters for the 500. You'll probably want a USB adapter like PAC USB-GM1 and a powered antenna adapter too. SiriusXM is an add-on module for most aftermarket head units. I didn't do this so can speak to it directly.
  • Flash the RR with the 2016+ Fiat 500 firmware. Un-tick “Gauges” and “Vehicle Info” in the configuration. I am using firmware version 2.0 but only because that was the latest when I installed everything.
  • Connect the harness as described by the iDatalink 500 installation instructions, except connect all audio to pre-outs/RCAs. If your HU doesn't give you 4 RCA outputs you might be able to get high level to low level, but I don't know anything about that.
  • DO NOT plug in the OBD-II connector. It caused several faults and warning lights that required AlphaOBD and a 500e compatible dongle to fix.
  • The camera trigger never worked correctly out of the RR. I could manually view it just fine, but going into reverse would not reliably show/hide the camera. I spliced into the reverse lamp wire to get my trigger and ran that to the head unit. Tap into it however you feel comfortable. Posi-Tap, military splice, etc.
After you do all this you should have things working mostly like before. I have great audio, steering wheel controls, the reverse camera with the factory lines, reverse sensors, car play through the factory USB port. Head unit/amp stays on for 10 minutes after removing key or until door is opened. Uconnect app still works for your standard 3 year window.

Some other notes:
  • Parking brake signal is only triggered if engaged while the car is powered. You need a bypass or to turn the car on, re-engage the parking brake. This is a mild inconvenience when you want to watch video, change settings, etc.
  • I did not text AUX input as I do not use that, but it should work.
  • The factory mic is not exposed by the RR best I can tell. My Alpine came with it's own mic that I routed near the drivers sun visor.
  • The sat/GPS antenna adapter never worked right for me. Navigation would be completely messed up jumping all over the place. Again I used the included Alpine GPS antenna (mounted hidden under the dash.)
  • Software settings aren't really accessible any more - DRL, units, etc. RR and your head unit should have a section for it, but half the settings were missing. The others never really stuck. Also when messing with settings it would often remove my reverse camera lines. To restore I had to reinstall the stock head unit and change the setting back. AlphaOBD might also help here, but I never looked. Supposedly "my500e Prime" exposes these settings, but that's several hundred dollars and likely not worth it just for settings.
  • The stock head unit might be doing some camera processing - the feed was dark on my head unit and I had to mess with brightness/contrast in the video input settings.
  • I regret getting the ILX-F309, but that's a different thread :D
 

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Discussion Starter #6
Thank you! All that info will definitely help me out quite a bit as I go forward! I've got my RCA ends cut and ready for splicing into the stock wires.

So by my understanding of all this, the Meistro will 100% always be getting power no matter if the car is on or off and then it reads the cars state and controls the remote power for the head unit?

I'm still confused with the steering wheel controls. I don't see any wires for them that go into the head unit which is why I assumed it ran over the CAN bus. Did I just miss them? My aftermarket unit has 2 wires for them but also says needs a CAN bus adapter.
 

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I haven't checked the power draw, but the Maestro does get both constant and accessory power so I assume it's capable of being powered 100% of the time. I haven't had battery drain issues so it's either smart enough to shut down after the RAP window (10 minutes or door open) or it goes into a low power mode.

For the SWC - Is your head unit is Maestro compatible? If so it's handled by the 4 pin data cable that goes between the HU and RR. Not every head unit supports Maestro data link though. I think you'll be fine without official support, but you'll need to use the alternative data cable. It's listed as "18" SWC harness (4-pin to 3.5mm/bare-wire)" on the package contents.
 

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Discussion Starter #8
For the SWC - Is your head unit is Maestro compatible? If so it's handled by the 4 pin data cable that goes between the HU and RR. Not every head unit supports Maestro data link though. I think you'll be fine without official support, but you'll need to use the alternative data cable. It's listed as "18" SWC harness (4-pin to 3.5mm/bare-wire)" on the package contents.
I'm confused as to where the control wires go after they leave the steering wheel. Does it go into CAN or are there separate, dedicated wires for the controls? You had mentioned issues with CAN and the 500e. Do some of the CAN features work just not a bunch? Sorry, thanks for walking me through this.

Anyway, this thread needs some pictures.

Got my 4 RCA cables spliced into the stock wires with power. Waiting for double DIN kit to test out mounting and ordering an LOC

108727
 

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Not sure about SWC. The Maestro RR does all the hard work to create a universal interface from each specific vehicle. It decodes the messages and factory wiring so you don’t have to. The RR will output 2 bare wires for SWC that go into your head unit.

As for CAN all I can say is a direct OBD-II connection (as the RR installation suggests) caused bad errors and warnings. Things like read/writing settings, reading TPMS sensors, “gauges” info, back up sensor visualization, etc work to varying degrees and are undoubtedly CAN powered. I disabled those features because fancy head unit graphics aren’t worth ESC and propulsion related errors.
 

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Thinking more about your “2 CAN wires” - that is exactly what the OBD-II on the Maestro RR is. The thing the threw errors with ABS and all sorts of other things when I plugged into it. Curious if you made any progress on this? It’s a good looking head unit. I’d love to get CAN stuff working and figure out if it’s the RR that’s the problem or just the car itself.
 
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