dei 509u ultrasonic sensors not working

Hello there all

I am in the process of installing a Viper 350+ with a battery back up, DEI 307t tilt sensor and DEI 509U ultrasonic sensors into my 2010 Ford Ranger. I have everything working correctly except the 509U sensors. With them set at max sensitivity I have to snap my fingers right at the sensor face (both sensors) to get a trigger from them. My 507T and 509U are both hardwired to the - Blue instant trigger which is also connected to a hood pin switch. I have both sensors diode isolated using one 1N4004 diode and the hood pin is not. Both are drawing power directly off of the constant 12v ignition (red) wire. The 307T sensor works as it should. Any help would be appreciated. The 509U sensors seem like their under powered (just a guess.) I have checked my connections. I have good grounds, continuity and have tested the diode. All appears normal. I have not installed it into the truck yet but have hooked it up to test and correct any mistakes before final installation.  

Robbie

Try installing in the vehicle, if you're testing in the open air or a large room they won't respond. Once installed the tilt sensor will probably give you lots of grief.

Thank you for the reply. The sensors are mounted inside the truck at the top of the A pillars and both are aimed at the top center of the rear window. I did reconfigure its three wire harness and added a 1N4004 diode stripe towards sensor on the - blue instant trigger wire going to the brain to isolate it from the tilt sensor. I have been testing the harness by laying the brain flat across the seats. I have the rest of the wiring figured out and tested. I just can't get these 509U sensors working correctly.Robbie

Your diode direction is OK but you will need another in from the hood switch. Frankly I never install glass break or U/Sonics waste of time, though I do believe yours is faulty.(Dual or single zone prox, much better). You also wrote "12V constant ignition(red)" in your first post. For future reference a constant is permanent and an ignition is only 12v+ with ignition, can be rather confusing.

Thank you for the correction. I meant the 12 volt constant red wire going into the ignition harness. Is running three sensors into one zone trigger ok?Robbie

Yes that's fine as long as they are diode separated of course. Early and more basic alarm systems use the same (blue) wire for trunk and hood. The trunk switch is usually factory and the hood switch aftermarket. It takes some experience and practise to get hood switches right and protect them, shrink sleeve the connector, water retarder etc. Without blocking diodes if the hood switch fails it will bring on the trunk light, leave that vehicle Fri-Sun = flat battery.

Well went back and checked the wiring and found that I accidentally crushed the sensor wire in the passenger side A pillar. I'd say I found my problem. I do thank you for your help and knowledge though. I appreciate your insight as well.Robbie

You won't be the first person to do that I can assure you.