Modifications to electrical system ND

Technical Area Electrics & ICE
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I’ve been playing with my ND soft top a bit the last few weeks. I started by wanting to fit a window controller to do one touch close, I had a few ideas but found mx5things online. £20 later I had a module that would control the windows post roof operation. Soldered it in and jobs a good un.
I didn’t want it to drop the windows on opening the roof however, I wanted it to roll them up regardless of opening or closing the roof. I contacted the seller who either simply didn’t read my messages or didn’t get the gist of my questions. I needed to know what the ramifications of twinning the outputs from the PiC16 would be. Turns out PIC16 uses open drain (npn TTL) so there are no ramifications. Twinned the up and down pins on the PiC board and only connected the ‘UP’ wires and it works a dream.

This got me thinking, what else bothers me?

Well I still didn’t have one touch closure unless I was operating the roof. So I decided to replace the PIC16 with an arduino nano. £3.55 and an hour coding. Now it is programmable mid cycle like the plug and play unit MX5things sells, it can open or close the windows on lowering the roof. Always rolls windows up when I close the roof. I also added a bit of code to recognise a double click on the up button, when it sees that it executes the 4 second close cycle, pushing down interrupts it as expected. Works great.

My next gripe was an easy fix, I did it before the window/roof mod actually. Pin 25 from the STOP/START unit kills the windows if you open a door with ignition off. Grrrrrr. Every time I stop my wife bolts to open her door as I’m closing the windows. So I have to put ignition back on… a simple fix was a 555 timer and a sub miniature relay. This bypasses the relay to pin TK on the R5F109 controller giving me a 30 second delay so I can operate the windows with ignition off and doors open. The windows still stop 20mm or so from top then close once the door is closed. A simple thing but makes me smile every time. Yes I could just close the windows before turning the engine off but I didn’t want to :rofl: hence the mod.

Next up a boot opener. Friends can never find that boot open button where it’s hidden, I have no release button in the cab. I was going to use a 555 to pull the relevant relay in from a dash button, but having found a full set of electrical drawings I found the ESU CPU synch switches the relay, so again arduino time. A second arduino was added, it was easy to add a delay so I have to hold the button for more than 0.75 seconds in case I accidentally bang it and have to get out and close the boot. Arduino being easy to configure I added a register for road speed from the dash CPU, once I’m doing more than 1kph it disables the function.

What next? Clocks/display/dash.
I hate the lane departure warning system with a passion, I have it turned off 24/7. The amber light tho, annoying. Used the same arduino as the boot release and dig into the dash, not for the easily frightened! Now the warning light comes on for 30 seconds when ignition is turned on then goes out. Same after a change of mode. I also did the same with the LIM and cruise lamps. Nice clean dash when driving now.

Fuel warning light is tiny and hidden by my big paws, so I altered that too. It now flashes 10 times 500ms on 500ms off before going solid when the level drops or ignition is turned on with low level. Then it flashes 3 times every 60 seconds and goes solid again, it’s more noticeable that way. You can stop the flashing by pressing the trip button once. It also returns to flashing mode after ignition off and on if you haven’t filled up.

The bus system makes it a pleasure to mod operations, it’s easy to mod hard wiring but means more panel pulling. What else is annoying tho? I want to play a bit more haha.

6 Likes
2

That sounds very interesting.

Can you swap a bus device for another and it will work or does it need programming to activate it. For example would adding a bluetooth module start working when added, or does something else have to done.

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The bus system will be looking for nodes, or addresses. Then it expects data to be regular and consistent. You can’t alter the code within it is locked down by Mazda in Japan. It is also a complex multi threading code, you don’t want to play in there. If the node is missing or data corrupt it will flag a fault.
All you can do is tell lies to it. So you intercept hardware inputs and manipulate them with something before deciding if you want to report that specific event has happened or not, and it may or may not have.
You can also simply monitor what is going on and manipulate real world field wiring as it comes from the modules. This is what you do 9 times out of ten.

Can bus wiring in cars saves tens of kilograms. It was started by BMW if I’m not mistaken, when in the early 90’s a 5 series wiring looms was trialed but to gain the desired control weighed in at 100kg. Can bus drops that by 80% and not only makes life easier but it’s as simple as uploading new software if you need to change the way something looks or works. Mazda do this regularly, sure you’ve seen it when they update firmware and everything works differently and normally more annoyingly. The possibilities are endless too as we now see some crazy tech popping up.

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What I am asking is what will happen if I replace the basic radio (type A) without centre display with radio with display (Type B)? Will it work, or will it require to be enabled by a dealer?

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Oh. No idea sorry :rofl:I’d imagine would be ok tho it’s not that critical a component

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The only problem is that I would have to buy it first without knowing whether it would work. Is it worth trying?

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Post a link I’ll have a look into it but it’s not that easy to know some times.

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I am trying exactly that today. Will let you know how I get on.

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image3024×4032 3.13 MB

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What would be interesting is to enable door locking / unlocking with speed. It is an option if you have a door lock button (as per US door/window lock) and by pressing door lock in sequence, you can enable auto door locking. (see the manual). Supposedly a dealer can enable this by software but they look at you blankly when asked.

Possible?

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There are a few things like that.

I do not have the display screen which I would like to upgrade to because I can find no way of swapping the display of miles to Km as it can only be done by using the display. There is also a change that can be made to the display of engine temp that has the normal value to be centre rather than squeezed over to the left.

I would like the windows to close from the remote as other cars can, and why do they not close after the soft top is closed, and instead remain half closed…

Any attempt to get answers from dealers and Mazda UK are not answered

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This is the type of screen but it needs a lot more than just this.

It would probably need other bits and cables. Would it need dealer coding?

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It would need coding yes. The cpu would have to know what it was. It would see ‘something’ but have no idea what. So it would have no idea what to with it.
It’s possible but highly unlikely that they have programmed lots of ‘if’ statements into their code, so ‘if’ it sees x, y, or z then jump to subroutine a,b,c… but that’s not how it’s generally done because you’d have thousands of dead routines taking up memory, and the way other routines would run or interrupt each other dependant on hardware present could be vastly different per set up. Some times adding a component isn’t simply about making the radio work differently, it can impact how other hardware acts so that has to be revised too. It all happens as a central upgrade.

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I understand that but this is a standard item in the majority of ND cars sold. Surely it would just recognise it and incorporate it on start up.

Maybe not, but at most, all I would expect is that the dealer needs t flip a few bits somewhere in the code.

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Adding drive away locking would be very easy. I can’t stand it but that would be dead easy to do.
Altering an lcd display isn’t too hard either. The issue with the temp gauge is how it collects and shares it’s data. Could be a faff around. I haven’t done much with LCD displays, maybe one day.
I would like to alter the gear shift display. I like that it displays current gear but not that it suggests when to shift. I’ll decide that thanks! Maybe I’ll pick on that next.

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The change to the temp display is an option in the setup of the ND2, but des not work on my ND1.

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It won’t. ND1 isn’t coded for it.

1 Like
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Oh well, I can live with it as it really does not matter much.

19

We can’t change what Mazda have done. We can only tell their hardware lies. Anything they haven’t coded we can’t alter.

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Adding drive away locking would be very easy.

I would like to alter the gear shift display. I like that it displays current gear but not that it suggests when to shift. I’ll decide that thanks! Maybe I’ll pick on that next.

Would love to have the drive away locking. My ND2 gives a hint to change gear, for example if I am in “4” the display will change to display “4-6” hinting when to change.