Spent ages (a week) trying to set up my 508d installed in the roof by the sunroof motor. Had to remove the top plastic cover for it to fit (gluing it to the bottom cover which has foil on as standard). At first it seemed okay and managed to adjust it so a face had to be right up to the glass, leaving 15 minutes or more after arming, and would not trigger if you walked or ran past within a foot. Seemed perfect. Now I find that in that adjustment it can warn away when a car parks up even 4 to 5 feet away. Other times it seems difficult to set it off when putting face next to glass, even after being armed overnight. Turn the warn away screw down a minuscule amount, and it won't trigger at all. Either seems to be too sensitive or not sensitive enough. Have also tried adjusting the installation position and angle with no luck. Where I park, I don't want to annoy the neighbours.

Thinking of getting a Crimeguard Omega AU94TM to replace it? Looking at the shape and size I hope I would not need to remove the cover to install in the same location.

TIA

 

I have never liked the 508D, always a pain to adjust, th AU94TM is a much better unit. 94

 

make sure you're adjusting the full trigger zone first, then the warn away. I have mine under the center console and warns away if the windows are down and you come within a few inches of the window opening and full trigger if you reach in more than about a foot. If windows are up I find it sometimes warns away when you put your face up to the glass, but always warns away if you move into a 5"x5"ish space between the mirror and the window.

also keep in mind to adjust away from fluorescent lighting for best results (or anything else around the 2.4GHz freq for that matter) not to say you wont be able to adjust it.. just for best results..

where do you have power and ground?

 

Using a Viper 1002 so power and ground are provided by the alarm's optional sensor port. The manual says this ground connection is controlled by ground when armed. Unfortunately I have no option but to park outside someone's kitchen (if I want to park anywhere near where I live) which will likely have a fluorescent light, but did not notice if their light was on or not when it warned away.

I guess it's also possible I have damaged it through ESD or unintentionally disturbed the factory pot with removing the cover.

I have ordered an AU-94TM off ebay and hope to give that a try.

 

try cutting power and ground off of the harness and connecting the 508D side straight to the same 12V power source as the alarm, and the ground to the GWA from the alarm. There are some cases where that port doesn't have sufficient current for the 508D as a direct plug-in.

 

the beam on a 508d expands after a time period of no activity. you have to adjust it according to the expansion. a dei tech explained it in one of the snake pit trainings several years back but i cant remember all the details. the 508d's on my cars work flawlessly. i love em. i remeber you have to adjust it, wait for beam expansion, then test.

 

Yeah that's what I was doing, overnight too and achieved those results.

If the 508d could not get enough power from the alarm brain I'd have imagined this would have come up before and I'd have read about it on my forum searches? The other sensor connected is the DEI tilt, not sure if that saps too much power?

Just received the AU-94TM and can't believe how small it is compared with the 508d. If under the roof liner by the sunroof motor is not a good installation spot and is causing the adjustment issues, then I am sure this will squeeze somewhere under the centre console.