dual zone proximity sensor

My car is fitted with a DEI 508d proximity sensor as far as I am aware, and appears to be mounted under the centre console area on the floor of the car, thats if its the clear box with two lights on that I think it is? Anyway, the sensor from most areas works fine, the warn away works when you are stood upto the car as soon as you look into the window at either side, and the full trigger is activated just as you put your arm through either window. The problem is, the car is only a small hatchback, yet when the boot is open and if my arm is placed in the warn away triggers will sound, but to trigger the full alarm my arms need to be in the back seating area. Is there a way to increase this without making it too sensitive elsewhere?

As far as I know, not without adding an additional sensor. The sensors use a circular field to trigger so increasing the radius affects everything. That is why a lot of people will use 2 sensors; one up by the front of the car, and one near the rear to help achieve more of an "oval" protection zone.Kenny

Owner / Technician

KKD Garage LLC

Albany, NY 12205

Make sure the mounting tabs are facing the front and rear of the vehicle. The ideal location for the sensor is in the center of the vehicle as possible. Also there are two dials on the sensor that can be adjusted to increase/ decrease the warn and full trigger zones. The warn away has a green LED and full trigger has a red LED. I can't find a manual for the 508D but it explains how to adjust the zones. If this isn't sufficient you may have to add a additional sensor but I cant see that with a hatchback.I drink current, eat ohms, and bleed voltage

I gave up years ago on small hatchbacks in the UK, I just concentrated on the driver's area making sure there's a trigger and connected to the alarm, even though I roof mount them where possible. Funnily enough the only car I've ever had real success with was an X5 using Clifford's digital dual prox sensor that's only compatible with G4 and G5. Even my own with a 508d in the roof lining, centre roof, I can't reach the hatch.

offroadzj, I understand...I was hoping there would be a simple fix but unfortunately not, would it be worthwhile adding a second 508d inside the rear hatch area? If that would even be possible to install a second sensor I am unsure, or even some ultrasonic sensors in the rear, although I hear these are temperamental. Pts760, are these the tabs which look like screw holes? These are indeed facing this way but the sensor is stuck down rather than screwed it seems, the adjustment screws are at the front offside edge of the vehicle. I have been given the adjustment instructions with the alarm but I dont feel I should adjust it for risk of messing it up, as if it is already perfect at the sides of the car surely these will be expanded with adjustment? The sensor has been placed under the centre console area as I say between the handbrake and gear shifter in a rather large gap between, I'd say it's as near the centre of the vehicle front and back wise as possible, any further back would be too near the handbrake I assume. Howie II, you may indeed be on the money there, it' seems to be a good trigger and warn away sensitivity for both driver and passenger area, even when sat in the back seat if activated and after a few seconds if I move about there will be a couple of warm away beeps before the siren triggers pretty much straight away, it's just the rear hatch area which doesn't trigger fully, only the warn away beeps are heard. At worst case this isn't a major problem as I only usually keep a wheel brace and tyre inflator in the boot, if a thief was to climb over to attempt to steal the car the alarm would trigger then anyway, but it's nice to have complete piece of mind. Thanks

I've never seen one that was actually screwed into place, my recommendation any way would be the roof lining, ground plane from the roof, no signal blocks from the chairs etc. What vehicle and is there a sun roof? Any yes I've often extended the cables to accommodate roof lining fitting, no adverse effects, heck you've got to run the antenna up that way anyway. Smart car aside you will NEVER cover a whole vehicle. The only problem with u/sonics is that they can be unstable if you drive t5he vehicle on a winter's night, then park it. The sudden temp. drop can trip them. Also of course you can't leave the windows open, but on a small hatch, Fiesta, 206 they DO cover the rear.

The roof lining does seem like an idea, if mounting upside down is possible? The only issue I would have is the roof lining is completely different to most vehicles in that it is a thin stretched vinyl type material not a thick furry carpet like item, I have a feeling the sensor would leave a bulge in the lining. Do you feel moving it to your roof would cover the boot area or would I still have problems if you say that full coverage will never be achieved? I shall leave the ultrasonic sensor idea as Iam not a person to cope with false tripping all the time. Thanks again

Again what vehicle. And yes as long as the emitting surface (top, screw flanges are on the bottom) faces the car it WILL work better.

Sorry, it's a Toyota vitz, if you know what that model is? I've just attempted to open the boot again and the alarm full triggered immediately which is quite baffling

Please don't try to be clever, I've done 'em all! Basically a Yaris, early version didn't have a trunk (hatch) light and we had to add one, later post 2005 (02 in China)had a trunk light, if you have one and it's connected to the alarm, that's your answer. Since this is a grey import I'm assuming a Cat I alarm was required by your insurers, from the 508d, I'm assuming it's either a POS 460/480 or a rubbish Toad. I probably know more about it than you.