cigarette lighter port always on..?

[porsche986spyder]

Yes, there is not way around it. I just unplug my detector everytime I get out of my car. If you forget, it should not kill your battery. But if you left it pluged in, eventually it would start to drain your battery. Radar and laser detectors don't really draw a whole lot of amps. Just unplug it when not in use.

My BMW also had this, I ran a toggle switch from the ignition to the dash so I could turn the car on or off with a switch without the key being put in. I have no idea how I did it, I originally put a switch inline with the power of the cigarette lighter. But after I added another cig lighter inside the dash, and added another switch for my iPod I could turn the acc on. It was great, I didnt need the key to put the top up or down, I just flipped a switch.

[MNBoxster]

Hi,

Most cigarette lighters are on-demand appliances built to DIN standard in which on-demand appliances are B+ (Battery Positive or constant Hot).

DIN is an abbreviation for the Deutsches Institut für Normung e. V, an institution of trade and industry responsible for the preparation of National Standards in Germany, similar to our own ANSI - American National Standards Institute. Since DIN had already created an electrical wiring standard, ANSI (as well as many other countries' standards committess) simply adopted it.

Early in the Industrial Age, it was determined that adopting a set of standards would insure consistency and interchangability in the design and manufacture of components from one supplier to another. Additionally, it allowed educators to ensure they were teaching standardized techniques in engineering and science disciplines to insure a consistent follow-on workforce for Industry.

These standards included everything from Pipe and Tubing standards, Screw, Bolt Thread size and pitch standards, to electrical connectors, packaging sizes for appliances (such as Din sized Radios) etc. There is even a DIN standard for electrical wiring. As such, a Car Manufacturer knew exactly how large a Radio would be from a supplier and could design the dash to readily accept it, etc.

In the electrical wiring DIN standard, it was decided to wire all on-demand appliances (such as cigarette lighters, door operated interior lights, etc.) to B+ (constant Hot), as having to energize all other electrical components (such as the ignition, fuel pump, Relays, etc.) was inefficient. This is the reason most lighters are B+. Hope this helps...

Happy Motoring!... Jim'99

[djomlas]

great info Jim,
my friend has a 530i and his lighter's power turns off w the ignition form factory, of course its a german car, so hows that possible then if the design is originally from good ol' Deutschland?

[MNBoxster]

Originally Posted by djomlas

great info Jim,
my friend has a 530i and his lighter's power turns off w the ignition form factory, of course its a german car, so hows that possible then if the design is originally from good ol' Deutschland?

Hi,

There is no requirement to adopt the DIN standard, and as I stated most car's lighters are Hot, but not all. I cannot speak to a particular anomoly, there could be many reasons such as alarm system requirements, etc.

But, more often than not, you'll find the lighter is B+ (constant Hot) for the reasons I've given...

Happy Motoring!... Jim'99

[FrayAdjacent]

I guess if someone really wanted to, they could wire a relay to a ignition-on circuit and the cig lighter socket, so that the cig lighter socket would be powered off when the ignition was off. That way, whatever is on the cig lighter circuit would still be on it.

I think I might try this simple mod. Wire the coil side of the relay to the power for the stereo... then route the cig lighter positive through the relay. BAM! It would turn off when the ignition is turned off!

Since I'll be getting into the dash anyway to move the climate control unit, it might be a decent little mod to do while I'm in there.

[Tool Pants]

UK Boxsters are strange. On some the lighter is hot all the time and on others it is not. We think it has to do with the year. The owner usuall finds out when trying to use a charger that goes through the lighter, because it will not work unless the lighter is hot all the time.

I have been on the Toyota message boards because I'm fixing up my old pickup, and it has been said that on Japanese cars the key has to be on for the lighter to work. That is true for my pickup.

You could rewire the lighter. You can use the ignition switch wire from the cell phone connector instead of the existing always on wire to the lighter. Or you could wire the detector to the cell phone connector.

[NickCats]

Originally Posted by MNBoxster

Hi,

There is no requirement to adopt the DIN standard, and as I stated most car's lighters are Hot, but not all. I cannot speak to a particular anomoly, there could be many reasons such as alarm system requirements, etc.

But, more often than not, you'll find the lighter is B+ (constant Hot) for the reasons I've given...

Happy Motoring!... Jim'99

Very strange. My 1998 MB C280 lighter's power turns off with the ignition as well

Nick

Gracias TP. I will hardwire my V1 this weekend.