dei 508t field disturbance sensor

Sorry, I meant 508D

if you have constant power and are using something other than ground when armed on the black wire then you will see the lights come on when the alarm is not armed.

OK. I guess what I should have said is, is it normal and acceptable for the lights to flash while the alarm is not armed. Unless it is defective, I'm assuming this is normal since DEI makes the 5901 and the 508D and it is a direct plug in to the MUX port.

yes. if there is a regular ground used instead of ground when armed the sensor is always on and the lights will come on when any motion is within range. that is totally normal. I always cut the black wire in the harness and connect it to the orange ground when armed. doing so puts 12volts to the black wire when it isnt armed therefore shutting the sensor off. it wouldnt hurt anything to leave it as is though.

Thanks, I might do that.  I read where it doesn't draw much power,  but sometimes we don't drive this car for several days at a time.

Do what you think is best, neither way will harm anything unless as you say the vehicle isn't driven for MORE than a week. Just a thought, how badly has it been mounted that you can see it?

Oh Howie, always expecting the worse. Actually, I located what I think is the perfect location. On this cars center console, in the storage bin, there is a removable bottom liner. It makes it easier to keep clean I suppose. When you remove the liner, low and behold  there is a rectangular cut out in the bottom of the storage bin. You are looking right down at the floorboard. I removed the console and mounted it directly under the cut out. It is pretty close to dead center of the car. Now all I have to do is lift out the liner if i need to adjust the sensitivity or check the pretty lights. But don't worry, I'll ask some more dumb questions soon.

WRONG! Now you have to be very careful about any coins, keys or other metallic objects left in there. They will ALL adversely affect it's workings plus of course the metal seat frames. The first choice is always the roof if possible.

I'd never heard of mounting it in the headliner before. Turned upside down I presume? This car has an electric sunroof so I think it is probably not feasible in this install. Seems to work OK where it is, but I'll watch the metallic objects.