Re: MK 2.5 head unit into a MK1 and MK 2

[Mike]

So alls going well with the install of the mk2.5 OEM audio unit with the making up of the patch lead etc but can't seem to get button illumination ?
The LCD display lights when the ignition is turned on but the buttons won't illuminate when the unir is powered up or when the car lights are turned on ?
Am I missing something or at least how are they supposed to come on.......... when the the unit is powered up from the on / off knob ????


I reckon there must be more than one bulb illuminating that lot ?
I can t see where "lights on live" goes to ..... its a bit of a head scratcher

So I have finally manged to sort it now with a combination of wiring diagrams and using my specs to look at wire colours !!
It seems the "inverted dimming" and "TNS+ " connections HAD to be made correctly to the cars loom that ISO connectors did'nt support (despite them being Mazda aftermarket units) so once this was sussed out and tested Eureka!! I soldered and shrunk wrap insulated a couple of extra leads to make a nice job and all is good.
Just taking 12 volts to these connections does'nt work..... it seems to have to go through the panel dimming circuit , which is fine by me because the radio now dims with everything else
So her is a How to as it does'nt really warrent a diagram just an explanation....
I'll leave it to others to move this post into relevant areas on sites

http://forum.miata.net/vb/showthread.php?t=321261


RETRO FITTING MK2.5 RADIO / CD TO MK2 (some wiring gremlins sorted)
The basic change from single to double din is straight forward enough as indeed are the main connections that the JO1 socket on the back of the unit connect to... as MM advised me a hands free loom that provides the male plug (which would be left in original donor car) would be needed , and an ISO connector for the male in the mk2 the other half of which can be discarded, So make a lead up with corresponding colours from your male JO1 to the female socket to plug into your cars loom.
This will comprise of 4 or 8 speaker wires (depending if you have rears) a permanent live (yellow) ign on Live (red) and ground (black)
Now the problem I had , illumination , find a "pin out" diagram for the mazda JO1 socket (google) and connect terminals E and G with 2 wires coming into the multiplug on the cars loom , they are black/red for E and grey/red for G this enables TNS (the night system) and "inverted dimming" so when you turn the cars lights on the buttons light up but also dims the LCD display slightly.
I snipped the 2 wires off behind the multiplug and soldered and heatshrunk some insulation on them ............ all this has to be done because it seems the ISO connectors produced for the multiplug in the MX5 does'nt support this wiring as the manufacturer would assume its for some aftermarket radio without mazdas dimming set up
Mike (its nice to give summit back !!)