USB kill switch

[fishbone]

I'm sure I'm not the first that is bothered that the Accessport continues to be powered on when the vehicle is shut down. Has anyone found or made the corresponding USB cable with an on/off switch?

[BAC5.2]

It should be easy. USB is 4 wires. One is + one is - for power, the other two are I/O wires. Just wire up a mini relay powered by 12V ign-on, and call it good. AP turns on when key is ON, turns off when key is OFF. Use fuse #26 for the power (ignition #2/Unit). That way it will get constant power once in the ON position, but no power in the ACC position.

 

You could even have a manual override built into this.

[MiniStiGuy]

Yeah as he has stated. It's not a difficult setup for USB.

[DocHolladay23]

good question and good info, I might try this! If someone does it before me I wouldn't mind some reference pics!

[dschultz]

Sure you can do that but the dongle is what is supplying the power to the AP. So what you really need is to switch the power at the ODB-II port. Just install the switch in the car side wire of pin 16. Or even remove that wire and take power from an ACC line and connect it to pin 16. Then the ODB-II port (and anything plugged into it) will only run when the ignition is ON or ACC.

[fishbone]

The idea is sound, the application a bit troublesome for me. I'm going to have to go identifying which wire is which. I definitely like the idea of cutting power to the OBDII port better.

[BAC5.2]

ACC power cuts off during starting. IGN is on only in the ON position, and doesn't cut off when cranking.

 

BUT, there are plenty of times, for diagnostic purposes, where you would want the OBD port to have power when the vehicle is in the OFF position.

 

I'd make a USB cable with IGN on/off functionality, along with an override for times when you want the AP to be on with the car in the off position. That way you aren't LOSING any functionality, only adding it.

[DocHolladay23]

yeah, flashing the vehicle comes to mind, I would deff rather find a USB route to go

[dschultz]

ACC power cuts off during starting. IGN is on only in the ON position, and doesn't cut off when cranking.

 

BUT, there are plenty of times, for diagnostic purposes, where you would want the OBD port to have power when the vehicle is in the OFF position.

 

I think that might be model year dependent. There are ACC lines on the 05/06 that do not loose power on cranking. One of them is to the info panel.

 

What can you do through the ODB port when the power to it is off?

 

As an option then a two way switch could be used.

Position 1) power from battery to pin 16

Position 2) power from acc or ON to pin 16

 

Or this could be simulated with a relay control and a switch.

The relay contacts would go between battery and pin 16. The control of the relay could be supplied from acc or ON. If you need power when the car is off a switch could be used to supply the relay with power from the battery, otherwise it would be off for normal operation.

[Platinum_Racing]

Since I know you like playing with hardware, what do you think?

http://legacygt.com/forums/showthread.php/usb-kill-switch-141199.html

 

Hmm... Interesting. If you're just trying to put an on-off switch on a USB plug the DIY is pretty simple.

 

The USB plug has 4 wires. The two wires on the end are + voltage (Red) and - voltage (Black). Pick which one you want to put a switch on, and solder a micro SPST switch on there with some heat shrink to protect the solder joints.

 

http://www.radioshack.com/product/index.jsp?productId=2062503

 

Just make sure not to put much stress on the switch. Its best to zip tie it to something or tape it to the rest of the wire to keep it from moving around. You don't want the solder joint to break.

 

 

Or you can use the relay mentioned earlier. Use both in conjunction to make a manual override.

 

Good luck!

[DocHolladay23]

Just realized I never posted the pics of this, I did it a few days ago and it worked great! Red wire is all you need to splice in the USB cable, here are some pics, I installed the switch under the mute button for my radar now, looks great!

 

http://i626.photobucket.com/albums/tt344/docholladay23/USBSwitch1.jpg

http://i626.photobucket.com/albums/tt344/docholladay23/USBSwitch2.jpg

http://i626.photobucket.com/albums/tt344/docholladay23/USBswitch4.jpg

[fishbone]

VERY nice! What mount are you using? I tried a bunch of phone holders ones, I like NONE of them because they are way too bulky. I am OK with using velcro, I just need some sort of plate to keep it held in place in the vent or somewhere non-intrusive.

[DocHolladay23]

yeah I'm using a modified cell phone holder that clips on the vent, it's just flat so I used velcro to hold the AP to it.

[fishbone]

Do you remember the brand? Did you have to cut/grind anything down?

[BAC5.2]

I don't understand why you'd want to keep the AP hooked up in the car all of the time.

[DocHolladay23]

You know what, I remember now I used to have a cell phone holder but that is actually a universal GPS mount, it came with a backplate that was just flat so I didn't even have to do anything to it really, I got it at Target because it was on clearance. As far as leaving it there, I don't have any gauges and like to use it for a boost gauge, but it's still just as easy to remove as before for when I go to any shady areas.

[ISAACD208]

Okay have the limited 05 Legacy gt 5 speed, changed my rear shock and now she just cranks and cranks, got fuel and compression, no spark. Did I have car to high to trigger a kill or safety switch?? & anyone know location of it or it have to do with computer??? Please help shes been sitting for months over this issue.