Factory NAV delete Rear and Side Mirror Defroster issue.

[VABAM]

Me and Navster have an issue with the rear and side view mirror defroster not working after deleting the factory NAV system. I have been digging through the FSM and might have found a solution.

This is mainly for Navster but anyone can jump in on this.

What I have below is not a fix. I’m over seas right now so, I don’t access to my Z at the moment (or for the next 7 months). I think I’ve figured out a fix but I need some one to check a few things first.

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Disclaimer: Please take all necessary precautions when working on this DIY. This DIY is for advanced users only! I’m not responsible for any damages. Also what I have below is based on the 2009 370Z FSM. Please check my work and if necessary check the FSM for your year 370Z.

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For some reason the way the NAV and Non-NAV control the rear and mirror defroster is different. The Non-NAV controls the defrosters via the AC Auto Amp and the NAV system via the AV Control unit. See below diagram. (BTW, Navster I did check the 2010 FSM and the mirrors are controlled by the same circuit as the rear defroster)



I believe it is fixable but I need a few things checked.

Before doing any of the checks below disconnect the battery!

- First check connector M66 that goes into the AC Auto Amp for pins 26 and 27. Are there wires going to these pins? If not stop here and let me know

- If there are wires going to pins 26 and 27 on M66, please do the following continuity checks. Check from M66 pin 27 to M123 pin 130 (BCM) and M66 pin 26 to M3 pin 9C (Foot well fuse box). Please see below pics for the locations of M123 and M3. Let me know if there is a connection or if it is open for both checks.

Please remember that all the pin outs in the below pics are from the harness/wire side of the connector.

Please let me know what you find!

BTW please ignore fuse 13 for now even though I have it circled. It might come into play later.

[SouthArk370Z]

Sinking terminal 4B (48?) of the fuse block to ground will activate the defogger relay. To be safe, I'd disconnect terminal 151 on the BCM. But you're probably looking for a more elegant fix.

[VABAM]

Originally Posted by SouthArk370Z

Sinking terminal 4B (48?) of the fuse block to ground will activate the defogger relay. To be safe, I'd disconnect terminal 151 on the BCM. But you're probably looking for a more elegant fix.

That might work but I bet the BCM is not providing a constant voltage at 7A.

[SouthArk370Z]

Originally Posted by VABAM

That might work but I bet the BCM is not providing a constant voltage at 7A.

Sinking that line to ground is exactly what the BCM is doing. The BCM is not supplying power to the relay coil - that comes from fuse 3 - but completing the circuit to ground.

[VABAM]

Originally Posted by SouthArk370Z

Sinking that line to ground is exactly what the BCM is doing. The BCM is not supplying power to the relay coil - that comes from fuse 3 - but completing the circuit to ground.

Opps miss read the wire diagram.

That will definitely work then.

But we are trying to make the button work.

[SouthArk370Z]

Originally Posted by VABAM

Opps miss read the wire diagram.

I had to cover one eye and squint.

Originally Posted by VABAM

But we are trying to make the button work.

If I understood what I read, then the "network" signals are not the same. Every time I've seen a UART used, that meant RS-232C (or some other RS-xxx serial protocol) and used for device-to-device (not network) communication. I'm guessing it's not compatible with CAN. I hope I'm wrong - I'd like to see you figure this out.

[VABAM]

Originally Posted by SouthArk370Z

I had to cover one eye and squint.


If I understood what I read, then the "network" signals are not the same. Every time I've seen a UART used, that meant RS-232C (or some other RS-xxx serial protocol) and used for device-to-device (not network) communication. I'm guessing it's not compatible with CAN. I hope I'm wrong - I'd like to see you figure this out.

I’m little concerned about that too but the BCM is the same on all models so, in theory the input for the Non-NAV wiring on the BCM should work.

[Navster]

Really appreciate everyone's effort and support especially VABAM. Please let me know step by step how I can use the push button on the 3 Rd knob to activate rear defrost and side mirror defrosters. Is there any way I can play with the circuit on the actual climate control unit?


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[VABAM]

Originally Posted by Navster

Really appreciate everyone's effort and support especially VABAM. Please let me know step by step how I can use the push button on the 3 Rd knob to activate rear defrost and side mirror defrosters. Is there any way I can play with the circuit on the actual climate control unit?


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I would love to give you a straight up fix right now but due the fact I don’t have access to a factory NAV deleted 370Z I can’t in good conscience recommend a fix at the moment. I need to someone to check those connections that I described in my original post. I have some concerns about where some of the wires are going on the NAV wiring harness. If I was home I would have a fix by now.

BTW Don’t get distracted by SouthArk. He’s just stirring the pot a little.

[SlickSix]

Sub'd for a fix. GL!

[VABAM]

Just as a FYI, I haven’t forgotten about this. It’s on my list of things to do when I get back State side in July.

[Beego27]

Hey guys, about to try this build myself in Australia and have been reading through all the threads to make sure I'm prepared. Not sure what models you all have, but I have a 2013 coupe with the correct service manual. The defogger wiring diagram is slightly different, could be something that will fix your problem/something Nissan indirectly addressed over the years. Looks like the mirror defoggers have been added. Particularly 9C is shown as being connected to the passenger defogger and ground as well as the A/C amp in parallel.

[Navster]

Originally Posted by VABAM

Just as a FYI, I haven’t forgotten about this. It’s on my list of things to do when I get back State side in July.

no worries hope fully before fall before the weather gets bad. Thanks

[DamnThatZGuy]

Sorry to hijack this thread but does anyone know if just the 2009 NAV screen alone can be swapped to a 2010 or later screen? I'm sure the wiring connectors on the back of the screens are different between the two but can I then just use a 2010+ wiring harness?

[VABAM]

Originally Posted by DamnThatZGuy

Sorry to hijack this thread but does anyone know if just the 2009 NAV screen alone can be swapped to a 2010 or later screen? I'm sure the wiring connectors on the back of the screens are different between the two but can I then just use a 2010+ wiring harness?

Probably not. Between 2009 and 2010 there was a major change to the NAV system in both hardware and software. For example, the 2009 system needed to be taken to a dealer to update the maps via a diagnostic computer but the 2010 was a set of DVDs that could be loaded by the owner.

It might be do-able if you swapped the whole system, not just the screen. How ever this most likely be not worth it time and money wise. Most eBay sales of the factory NAV systems are usually missing components due to the hasty removal from a junked 370Z.