Pio 3400 head unit hook-up questions... this used to be easy!

[dlarkin_dc]

It's been about 25 years since I last replaced HUs. These newfangled HUs are a new beast!

I'm using the Metra 7903 harness and mating that to the harness from the Pio 3400 and I've got some questions. From lurking about I've know this is the right place to ask! Here goes...


Is it so nessecary to use a ground point instead of the Metra harness Gnd wire? I've always use the car harness Gnd wire before and never had any issues with noise. Whatever the OEM HU is using is working! If it is best to use a remote Gnd point, what Gnd points can anyone recommend in the M5?

The illumination and dimmer wires (Orange and/or Orange-White) have me puzzled... The Metra harness only has only an Orange wire labelled, "Illumination", while the Pio harness has Orange-White described as, "Connect to lighting switch terminal." They sound the same, despite the mis-color coding. Am I right?

Where is the best point to pick up the reverse signal in the M5? Somewhere in the shifter stack?

Where is the best point to tap into the handbrake line in the M5? The Pio manual is asking for a tap on the positive/high side of the brake switch but doesn't mention if the HU is expecting the handbrake switch to be open (12VDC) or closed (Gnd.) when the brake is on or off.


Ah, such fun!

I apppreciate the help!

[dlarkin_dc]

I've been at this all evening and I've come across a gotcha. The Crutchfield pin-outs detailed in this thread...
http://www.mazdas247.com/forum/showt...ng-Information

Show the Pin 4 as, "Dimmer." The Metra harness shows Pin 4 as, "Illumination," and wire color is solid Orange. All the other pin-outs match, except that one.

...and the Sonicelectronix site identified the Orange wire as, "Dash Light Dimmer/Illuminations."



So, what's it to be then? Anyone?


Dave

[dlarkin_dc]

Pioneer support told me, on the phone, that the head unit harness Orange/White wire is expecting a 12VDC.

The head end presumes this means the car's headlights are on, the dash instrumentation is illuminated, it is dark outside, and the brightness of the display on the head unit should reduced.

I think Pioneer are wrong to use the standard dimmer color coding of Orange/White to pick up dash illumination signal.

I dusted off my trusty multimeter and confirmed the Orange "Illumination" wire from the Metra harness does carry a 12VDC signal when the dash illumination is on.

So the harness Ornage and the Pio Orange/White are connectable.

One down...

[Silentnoise713]

Pioneer support told me, on the phone, that the head unit harness Orange/White wire is expecting a 12VDC.

The head end presumes this means the car's headlights are on, the dash instrumentation is illuminated, it is dark outside, and the brightness of the display on the head unit should reduced.

I think Pioneer are wrong to use the standard dimmer color coding of Orange/White to pick up dash illumination signal.

I dusted off my trusty multimeter and confirmed the Orange "Illumination" wire from the Metra harness does carry a 12VDC signal when the dash illumination is on.

So the harness Ornage and the Pio Orange/White are connectable.

One down...

Look at this thread and contact the OP to see if he fixed his lighting issue on his Pioneer unit.
http://www.mazdas247.com/forum/showt...ghlight=dimmer

With your current setup, does your dimming func work properly? The first time I took out the Miata's radio, I was not able to locate the 'Ground' wire to bench test it at home. It turns out Mazda does not have a traditional ground wiring but instead uses the whole unit's chassis as ground. I haven't done dozens of system builds but this is that first that I've seen it used this way. Then there's the invert dimming too.

I haven't and don't plan to upgrade my HU so I don't know how the Mz5's is different but I image everything is probably still the same.

[dlarkin_dc]

Okay - Got the HU and steering wheel tie-in in and buttoned up in a rush before a road trip so no pictures sorry. If you've seen the Crutchfield masterguide, it looks like that torn apart!

I will say that it wasn't helped or made easy by Pioneer's installation instructions, or the differences in my M5 from the Crutchfield guide, or the Metra harness not having outs for the steering wheel controls!

But I will be putting my experiences on here over the coming days to make it easier for unsuspecting souls eager to jump in.