dei 509u sensor placement

I am on the last leg of my alarm installation and have reached what i hope to be the final snag in my voyage. When trying to install the 2 sensors in the car i noticed they look hideous wherever i placed them. The only viable place i found is where the dash meets the A pillar as shown: The only problem is that the curvature of the dash will cause slight interfere as shown here: Will the 509U function correctly in this location or should i find another location??

Best working position is top of "A" pillars. The position you showed will also get false triggers from the adjacent air vent.

Thanks for the prompt reply. I tried to hide them at the top of the A Pillars and it look hideous regardless of where and how i would mount them. The vents should not be a problem as they will never be on when the alarm is armed. My concern regards how the ultrasonic waves travel and if the interference presented by the dash would cause the 509U to be significantly less effective.

I agree with the hideous point but..... Frankly I'll never use them rather a single or dual zone prox which is more reliable, faster to install and you can leave the windows vented or open. We've been using the ugly mustards for over 20 years in Europe and you must get them high up and out of the way of air movements.

On 90s Mercedes I used to flush them into the ends of the dash facing into the car but is your space enough? Again, away from air vents.

When the alarm is armed, the car is stationary and there is no power going to the blower motor. Can you explain how the air vents can set off a false alarm? For my next vehicle i will definitely use the proximity sensor but for this one, i wanna make this sensor work.

howie ll wrote: On 90s Mercedes I used to flush them into the ends of the dash facing into the car but is your space enough? Again, away from air vents.

There is no room anywhere on the dash except for where it is right now.

Leave the vents open and AC or not air will still pass through. Even better freezing cold night, drive a few miles and then park the car, as the temp drops the air gets more dense and voilà it triggers the u/sonics.

Ahh yeah that does make sense. I decided that im going to mount the senors at the top of the A pillar. To make it look a little bit less ugly i am going to mount tweeters there as well and try to play it off as a special component tweeter package. Thanks for the help howie ll