[Kwajtrader]

With the Z4 cooling fan under my belt I’m on to project #2, an ultrasonic curb distance sensor to warn of low curbs that are below the current PDC sensors. This is when it's not convenient to back in.

I’ve got a prototype Red/Yellow/Green stoplight circuit wired up and found what looks to be a good place to mount the sensor under the front bumper, but now the question is whether to keep it all under the hood with a display mounted in the center of the hood just under the lip, or to run it into the cabin and have some kind of notification there like an increasingly rapid beep. In either case I need to power it under the hood, or run wiring through the firewall. I saw the 12v jumper post and thought that may be a good place to power it from but I've got several questions I could use some help with:
1. Is that 12v jumper post active at all times or does it disconnect at power down, or any other time?
2. Are there other easy 12volt or 5 volt access points under the hood to tap into power. Do any of these shut down when the car goes into sleep mode?
3. Is there easy access to the cabin via a firewall plug or access port for running wiring?

Thanks in advance!

[Pprior]

You might not be the hero we want but you’re the hero we need. Rock on Garth

[Kwajtrader]

Originally Posted by Pprior

You might not be the hero we want but you’re the hero we need. Rock on Garth

Or I have just way too much time on my hands….

[stlcdr]

Are there electrical schematics readily available? If there are, I’d expect in the several hundred dollar range, or only available to authorized service centers.

I like to tinker, but not without schematics, and especially not on a German vehicle!

[RigaTony1982]

Anything useful in these technical guides?

https://g29.bimmerpost.com/forums/sh....php?t=1655664

[Kwajtrader]

Originally Posted by RigaTony1982

Anything useful in these technical guides?

https://g29.bimmerpost.com/forums/sh....php?t=1655664

Thanks. These docs seem to imply that the jumper terminal under the hood is always connected to the main battery, so if I use that I'll have to remotely put the ranging circuit in sleep mode to avoid draining the battery when it's not in use. I'm thinking a simple keychain style pushbutton remote inside the cabin to turn it on for say 3 minutes before automatically shutting off again. So many ways to skin this cat...

[RigaTony1982]

Originally Posted by Kwajtrader

Thanks. These docs seem to imply that the jumper terminal under the hood is always connected to the main battery, so if I use that I'll have to remotely put the ranging circuit in sleep mode to avoid draining the battery when it's not in use. I'm thinking a simple keychain style pushbutton remote inside the cabin to turn it on for say 3 minutes before automatically shutting off again. So many ways to skin this cat...

Credit to BMWGirlFL , who pointed me to those guides for a question I had last week

[Kwajtrader]

In other news, based on a suggestion from Tekpro007, after some thought I added a second speed to the Z4 wireless charging pad cooling fan, so now it has a High/Off/Low option vs. just On/Off. For his I added a slower speed in addition to the original reduced speed version that is a a little quieter, but for high temp climates I can offer a higher speed (fan running at full speed) but it'll be slightly louder than the original when in the high speed mode. I also just got my Bambu Labs X1 carbon 3D printer, which is not a car thing, but is pretty cool if you're a nerd like me.

[Kwajtrader]

First, thanks to Stan Diego and others who provided me with the cabin filter removal instructions. That got me to the view in the second photo below.

I’m getting closer to finding a way to route wires through the firewall, but I’m not sure exactly how to proceed. The first photo is the compartment under the hood on the passenger side. Does anyone know if that ~2” circular plastic thing is just a hole plug that can be pulled out from the engine side or if it serves another purpose? Also on the left is a an~ 6” diameter plastic thing that looks to be a cable pass through. Can I just drill a hole on the edge of that to pass wires into the cabin? On the cabin side opposite the 2” plug is padded gray insulation (see the second photo). Does it serve any other purpose? I don’t want to start cutting anything apart without knowing what I’m getting into.