Adding 508D proximity sensor to factory Chrysler

2015 Jeep Wrangler Unlimited Rubicon
Factory security & remote start
DB All 2 and Viper VSM250 Smart Start

I would like to add a 508D sensor to protect the Jeep when I have the doors and the top off. I'm aware of the limitations and issues of these sensors, and have used them before with good success. However, I can't figure out one wiring detail.

One easy way to integrate the sensor is to connect it to the tailgate switch wire via a relay, which does set off the alarm. However this wire also causes the "tailgate open" warning to come on in the dash. So if the 508D is always powered, it will constantly show a warning on the dash, and chime. Also I'd like to have the warn-away zone wired to a small siren and the dome lights, which again, would go off while driving. I have not been able to find any wire that is powered or ground only when armed. A manual switch would be less than optimal for both security and convenience reasons. Any other ideas?

I'd probably also add a hood pin switch going to the same tailgate wire. Believe it or not, they didn't protect the hood at all with the factory alarm! But that's not as important as the motion, I just mention it in case anyone has thoughts on that or a better way to protect the hood.

I'm open to other hardware and solutions that get to the end goal. I want to be able to arm/disarm with either the fob or the Smart Start system, not extra fobs or lose functionality of either system.

You'll need to boost the output current to the trunk trigger unlikely to work with factory alarm otherwise. No idea where you're going to find a "ground when armed" unless you place a latching dual coil relay from the vehicle lock motor wires.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

I will be using a relay for the trunk trigger, of course.

I hadn't thought of the latching relay and motor wires. Are you talking about the 611T? Is this something you've done, or seen documented? Would it be reliable? It seems like a pretty easy solution since the entire harness runs by the passenger kick and is easy to connect to. I'd have to use the tailgate lock wires, since the Jeep knows when the doors are off, and probably doesn't send power to the non-existed locks then.

You can use that but look up Omron dual coil latching relays 12 Volt coil, Farnell, Mouser etc.
A lot cheaper. Fed when lock and unlock motor wires go to 12V+


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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

I did a little searching and I'm led to believe (maybe wrong) that this method could easily result in the 508D being disabled when armed and enabled when disarmed. As I understand it, hitting lock on an already-armed/locked car would result in the relays turning off, right? This is likely to happen; my household has a habit of just making sure the cars are locked and pressing lock on the keys hanging in the kitchen before going to bed. Not the end of the world, but I'm trying to fully understand the situation before doing it.

Thanks for your info and quick reply, it's leading me to some solutions that nobody else thought of.

Absolutely not use this:-
Manufacturer: OMRON ELECTRONIC COMPONENTS
Newark Part No.: 82X7238
Manufacturer Part No G5RLK1AEDC12
About $5

That's the Farnell number, I used these over 20 years ago on a Clifford Solaris with only one aux, used it as a trunk release with alarm on, headlights with alarm off.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

The relay grabs the 0.8 second POS on lock to LATCH it so you've a constant ground, then when you unlock it grabs the unlock 0.8 second POS pulse to open the circuit. How do you think an alar's ground when armed works?
This is an earlier Omron showing typical circuits:-
284_omron_g6ck-_2114p-us12dc.bmp

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Well that's simple enough, thanks. Now to find the lock/unlock wires in the harness...

Driver or passenger kick panel, going into doors. Use the driver's in case you have priority unlock.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Driver kick panel, black 14 pin plug at door loom:-
Lock = tan/white pin 8
Unlock = tan/light green OR tan / YELLOW pin 1

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Thanks, you're fast! Is that for the doors, or for the tailgate? I believe the doors may not be powered at all when they are removed. Just a guess, based on the fact that the Jeep disables many things when you take off the doors. For example, the flash to pass and headlight switch stop working, so someone can't just walk by and screw with your lights/kill the battery. I'll go test it.

Ordered the relay from Digi-key, really cheap, reasonable shipping.

Excellent point on priority unlock, if the door wires behave the way I expect, then I'll need to disable that so the tailgate always activates. You've been a huge help.

Can't do a thumbs up but all the best!
Assuming a factory alarm can you get a wiring diagram?
There might be one or two wires which change state when the alarm is activated.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

If not the doors, then the tailgate motor wires.


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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.