Radar Detector Hardwire Question?

[ZeroG]

Have any of you hardwired your radar detector to your car?

I recently got a V1 that I hardwire to my car and was wondering if someone new of a better place to get a hot and a ground.

At first I tried to use the sun room wiring ecept that all the circuits are open and the when I would attach the V1 harness it would close the circuit and either open or close the sun roof based on what wires I had connected it to.

In the end I wired it through the interior dome lights. I used the purple wire with the white stripe as the hot and the brown wire with the black stripe as a ground. This seems to be working except for one thing. I think the interior light is wired through the central locking system because when the car is on the detector is on and when it is off the detector is off, however if the car and the detctor are on and you open the door when the dome light comes on the detector goes off, and then turns back on when you close the door and light goes off.

It's not that big of an issue I would just like it if when the car is one the detector is on and when the car is off have the detector turn of regardless of the door being open or not.

I looked all through the Bentley and could not find a wiring diagram for this. Any help would be appreciated.

-Chad

[GDB]

It would take some work, but you could always used the switched power for the radio, or run it straight from the ignition switch.

[1996 328ti]

Best thing is to find a power source tied with the ignition.
I have mine mounted near the sun roof switch and run the wire across the headliner, down the A pillar to the console. I tap off a wire that goes to the heated seats since the heated seats are only powered when the ignition is on. I also have the hidden display in my ash tray. It is not a great spot but I like to be able to close the door when I don't need to see it.

[aceyx]

tap into the violet/white wire for the hot connection. it's only live during accy, run and start.

[ZeroG]

Originally Posted by aceyx

tap into the violet/white wire for the hot connection. it's only live during accy, run and start.

Thanks for the feedback I will look for that wire this weekend.

I assume that the purple/white wire is for the dome lights?

-Chad

[aceyx]

from what i remember, yes.

i wired my own car differently (from cigarette lighter, with a switch to turn on/off without reaching up)

[robcarync]

bringing it back from the dead, i know, but similar question:

i tried to hardwire my radar detector to the dome light (little circular one). i soldered it directly to the circuit board actually so i didnt have to cut up wires. with the light bulb in, the detector acts as a jumper and the bulb would always be on when the RD is on.

i took the bulb out, so the RD would be on when the switch is flipped, and i could turn it off by flipping the switch. that worked except whenerver the light in the middle turns on (IE: door open, need to read something, etc) it uses too much power and the RD goes off until the middle light goes off.

and actually now my RD is fried and wont turn on at all, even with the cigarette lighter adapter. luckily it is very new and i can return it...but i need a new idea of where to wire it to.

ideally id like to have it so the car gets turned on, the RD is on, car goes off...RD goes off..

but if all else fails i could run it across head liner, down a pillar, wire it into the cig lighter, and use a switch so i dont have to reach up...

but i really would love to find a wire in the sun roof panel i can tap into without causing issues with the lights and what not...

has anyone used the violet/white wire to see if it works? didnt chad say he used to the purple/white wire (same wire maybe?)

i feel like using the wire may still cause the issue that im having with the RD cutting out whenever the other light gets turned on...

any input?

[zboot]

how about the cell phone connector underneath the cup holder center thing? I'm going to hardwire my (switched) inverter into that source and hide the inverter inside that area. . .

[John Firestone]

According to the ETM, the .5 mm^2 purple/white wire powering the reading lights with the ignition in positions 1/2/3 should do you, as mentioned a couple years ago. If you don't have maps lights, you likely won't have the wire and have to look elsewhere.

[robcarync]

I have the little circle lights and the fuse looking light in between them...so tap into the purple white wire....powering the reading lights...is that the little circle ones?

I'm just wondering if it would cause any issues with the RD turning off when the door opens/when the other lights are turned on....

like chad said... he used the purple wire with the white stripe and it caused issues with it turning off when the center light is on...so it still wouldnt solve the problem though...

if i am understanding right, i essentially already did that but instead of tapping into the actual wire i just soldered it to the back of the circuit board that the light was on.

and is this violet/white wire the same as the purple/white wire? or is one darker and the other lighter in color?

im confused...Chad says he tried the purple/white wire but has problems...aceyx suggests the violet/white wire, and chad says OK he will go look for it...

are they not talking about the same wire?

[John Firestone]

I am pretty sure everyone is thinking of the same wire. I called it violet/white -- no, sorry, ACK! I didn't.

I must have suffered a brief brain fade a few hours ago from working too many hours on a project. I should have called it violet/white because BMW labels it VI/WS = Violett/Weiß on their drawings.

I am having trouble imagining how the interior lights could affect the VI/WS wire unless the ETM is misleading me (it sometimes does) or the radar detector ground wire somehow didn't get connected to ground. The symptoms suggest the detector's ground wire was tied to the interior lighting signal.

[ATF]

Just double check all of your wiring with a multimeter before you start soldering. Also you probably need to check how much power the radar detector sucks up to avoid damaging anything else. The car phone connector sounds like a good idea, but if you want your radar detector up by the sun roof I guess that poses a problem. Another thing to keep in mind, my radar detector has one of those 360 Degree laser detectors and requires to be placed so it has a clear view of the back windshield and the front windshield, so it eliminates that stealth spot in the ashtray (which I still might do because if I'm getting hit by a laser gun, I'm probably toast in the first place..)

[robcarync]

I did check everything with a multi meter before soldering...my Pops is an electrical engineer and he helped me.

he guessed that the middle light probably sucks more power and doesnt leave enough power for the radar detector, which is why it fades out, then fades in when the light goes off.

but the way it was soldered directly to the circuitry, the little circle light could no longer be used because if the bulb is in, it will be on whenever the RD is on...and then whenever the middle light comes on the light doesnt leave enough power for the RD (from what im assuming/trying to figure out)

also the way it was wired, the switch that used to control the circle light, now controls the radar detector.

so if i just tap into the V/W wire and the brown wire for ground, everything should work alright?

i think soldering directly to the circuit board made things more complicated...

on a side note, anyone have a clue as to why my RD no longer works? wiring it to the circuit board shouldnt cause it to get fried should it? im kinda scared to hardwire to the same place again after my new RD just got toasted...

[aceyx]

Rob; can you take a picture of your work? Might help with the diagnosis.

I just looked at my lights, there is are two ground (brown) wires and a brown with red stripe. I'm hoping you didn't confuse these.

As far as the violet/white, I had the info from Ron Stygar's site so I'm inclined to believe it works. If not, the guy would have fixed it or rigged some inexpensive contraption to make it work.


Also, are you using an in-line fuse on the powered lead to the detector? Most have them in the lighter socket adapter. You'll need to use the same (power rated) fuse.

[John Firestone]

Rob,

Everything you describe is consistent with tying the radar detector's ground line to the ramped (PWM) power for the middle interior light. The interior lights have a low enough resistance when cold to pull the radar detector ground close to ground so that it would work, at least at first.

The reason it may no longer work is that there are other consumers on and upstream of the F43 line feeding the VI/WS wire and the detector's +12V power input. Likewise, these loads will pull the detector's +12V power input to ground when you switch the ignition off. If you left the ignition off and then did something that caused the ZKE to turn on the interior lights, the detector would see +12V on its ground line and ground on its +12V power input -- and a pretty low impedence, power supply, polarity reversal. Of course, you are supposed to design automotive electronics to withstand such abuse but, unfortunately, not everyone is so careful.