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space_out_today Samba Member
Joined: February 13, 2017 Posts: 21 Location: Southern California
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Posted: Mon Jun 09, 2025 6:17 pm Post subject: Hornet 723T security system de-installation advice |
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Hey there,
Problem: Old Hornet 723T security system/kill switch removal.
I have a few projects in progress on my van, one of which is a starter issue (separate thread) that I think I have overcome. The starter issue got me thinking about an old security system that has been in the van prior to my purchase of it in the late 90's.
There is a kill switch to the left of the automatic gear select, under the side dash nestled under a small fin (if that makes sense). There's an LED that fits inside one of the dash knockouts (by the hazard switch, etc.). There was an audible alarm siren that I disconnected years ago. I did this because the alarm would sound if the battery voltage dropped (had a slow drain, it's fixed). The alarm would then completely drain the battery.
I removed the front seats today to service them and decided to trace the wiring out. Removed the instrument panel and the loosened up the fuse box to get a better look. I ended up finding the control unit after tracing the wires back. The control unit is just to the left of the break peddle, barely peeking out. You can see it if you peel the carpet back.
I cannot find a wiring diagram for the Hornet 723T. I look at this unit as a ticking time bomb...something that is going to fail at some point and render the van unstartable. Also, as you know the area behind the fuse box is not a spacious one.
Some behavior: When I remove the ground strap of the battery for whatever reason then reattach it, the LED will be in an intermittent blinking mode. The toggle switch is then set to whatever direction is opposite, then back AFTER KPII is set, and the van will then start. Otherwise, it's killed.
As you can imagine, without the wiring diagram, I really don't want to mess with this BUT I only see this as a liability. I'm interested if anyone has run across this, or has any suggestions.
Thank you. |
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kamzcab86 Samba Moderator

Joined: July 26, 2008 Posts: 8420 Location: Arizona
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Posted: Mon Jun 09, 2025 6:47 pm Post subject: Re: Hornet 723T security system de-installation advice |
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732T manual: https://www.manualslib.com/manual/795883/Hornet-732t.html?page=9#manual . Not the same, but surely there's some similarity?
I removed my Cabriolet's Clifford alarm (no kill switch) ages ago... PITA, rat's nest of wire. Fortunately, the installer didn't mess with the factory wiring. _________________ ~Kamz
1986 Cabriolet: www.Cabby-Info.com
1990 Vanagon Westfalia: Old Blue's Blog
2016 Golf GTI S
"Real knowledge is to know the extent of one's ignorance." - 孔子 |
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skemems Samba Member
Joined: February 23, 2017 Posts: 245 Location: Oregon
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Posted: Mon Jun 09, 2025 9:02 pm Post subject: Re: Hornet 723T security system de-installation advice |
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You dont really need to have or know the wiring diagram to remove your alarm system.
All wires on a alarm systems are just tapped into existing wiring with exception of starter wire (for kill switch/starter kill). Meaning you can just follow wires to were its connected and cut the wire going to alarm, use electrical tape on any exposed wire. The only wire that will need to be re-connected is the starter wire from ignition switch coming from the steering column. Use crimp or solder to re-connect.
If you have aftermarket door locks you will loose power lock/unlock you have with they key fob.
There shouldnt be very many wires...12v constant, ground, ignition, door triggers, parking lights, horn, pwr locks (if aplicable) and two wires for starter wires that need to be re-connected.
space_out_today wrote: |
Some behavior: When I remove the ground strap of the battery for whatever reason then reattach it, the LED will be in an intermittent blinking mode. The toggle switch is then set to whatever direction is opposite, then back AFTER KPII is set, and the van will then start. Otherwise, it's killed.
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This is normal behavior of a kill switch, starter kill is activate after loosing power. This prevents someone from disconnecting the power to "de-activate" the kill switch to steal the car.
If you remove the alarm I would recommend installing another form of security/theft prevention. _________________ 87 VW Westfalia - EJ25
86 VW Westfalia - EJ22
85 VW Westfalia - WBX 2.1 project |
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space_out_today Samba Member
Joined: February 13, 2017 Posts: 21 Location: Southern California
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Posted: Tue Jun 10, 2025 2:49 pm Post subject: Re: Hornet 723T security system de-installation advice |
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Thanks kamzcab86 and skemems for the info.
I was going through the wiring diagrams today (before seeing the most recent post) and was very curious about how the necessary wires that the control unit requires are attached. This is good news.
I'll post an update shortly.
Thanks again! |
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space_out_today Samba Member
Joined: February 13, 2017 Posts: 21 Location: Southern California
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Posted: Tue Jun 17, 2025 9:27 pm Post subject: Re: Hornet 723T security system de-installation advice |
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Ok, Houston, we may have a problem.
I dove into the alarm removal this weekend and got to a point where I paused, read more from both the Bentley wiring diagram and the posted Alarm installation guidance (thanks again!), and some other diagrams (GW, etc.).
The Siren, plug in LED, valet switch, and control unit itself were identified and removed. I taped off the wires that were spliced and remained and marked several candidate wires that still had the splices on them. When I went in today I decided to continue. There was a 12V connection to the fuse/relay panel with an inline 10A fuse, and a ground that was attached to one of the trees on the driver side. There was also a splice ground that forked off into the side frame, I believe for rear of van ground.
I was certain that the inline fused wire would reveal the other splice (lots of tape on all the splices). It didn't though. As I pulled it out it must have powered the control unit and I missed it. That's not a great description, I know.
Jump to now. Again, based on the guidance I was expecting to see possibly red/10 broken and I'd be able to direct wire it to the voltage supply (where the fused connection) was, but after looking at 97.56 again, I'm clearly uncertain. I just cannot find what I was expecting.
What I did notice is that behind the fuse panel (approx position 8 ) there are 2 larger gauge red wires cut. I did not cut them. (Load reduction relay?)
Curious about inputs if anyone has some time. I have to refresh my wire diagram reading skills and process this a bit more, but any thoughts are much appreciated.
Thanks! |
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skemems Samba Member
Joined: February 23, 2017 Posts: 245 Location: Oregon
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Posted: Wed Jun 18, 2025 4:23 pm Post subject: Re: Hornet 723T security system de-installation advice |
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Uploading some photos followed by what your talking about will be helpful.
space_out_today wrote: |
The Siren, plug in LED, valet switch, and control unit itself were identified and removed.
There was a 12V connection to the fuse/relay panel with an inline 10A fuse, and a ground that was attached to one of the trees on the driver side. |
Did these also go to the alarm module? If so they can just be removed.
space_out_today wrote: |
I was certain that the inline fused wire would reveal the other splice (lots of tape on all the splices). It didn't though. As I pulled it out it must have powered the control unit and I missed it. That's not a great description, I know.
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If your not sure, its easier to trace/follow wire from alarm plug to 12v source, same with ground wire. 12v could be spliced into an existing wire or connected behind fuse panel.
If you have any other non factory items installed, these could be powered somewhere behind fuse panel. Fog lights, aftermarket radio, etc... additional fused wires could go to those.
If your just removing the alarm just follow wires from the alarm system and remove. _________________ 87 VW Westfalia - EJ25
86 VW Westfalia - EJ22
85 VW Westfalia - WBX 2.1 project |
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space_out_today Samba Member
Joined: February 13, 2017 Posts: 21 Location: Southern California
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Posted: Wed Jun 18, 2025 7:23 pm Post subject: Re: Hornet 723T security system de-installation advice |
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Hey there friends!
Here's a few pictures. Unfortunately, as the pictures show, the unit is completely removed now.
Yep, The Siren (r/bk wires in pic), plug in LED(twisted r/bl), valet switch(grn/y), and control unit itself were identified as wired in to the control unit cut to remove the control unit.
See the picture of the 12V connection to the fuse/relay panel with an inline 10A fuse, and a ground that was attached to one of the trees on the driver side. That was also attached to control unit, with some other wires spliced in that seem to loop back to the LED and the switch.
You can see the cut wires behind module 18. I don't know if this is related or not.
I do have an aftermarket horn, an accessory relay and fog lamps that I installed myself, so I am tracking those connections.
Also have a picture of the unplug ignition switch socket.
I have 2 blk, 1 r, 1 bk/y, 1 r/bk, 1 gy/bk,
The bentley (97.56) shows bk-20, blk-16, r-10, bk/y-10, r/bk-18, r/bk-10, gy/bk-20
It looks like I'm missing a r/blk 18, but there's no evidence of cutting, so I'm thinking it's the model van I have (87 GL wolfbg edition) or it's spliced down-circuit.
I thought I would find one of those wires coming off the switch interrupted and reconnected into the control unit, then after removal a cut wire that would need to be respliced or reconnected to either the ground or the constant 12V bus on the back of the fuse panel. But I didn't?
Would you say the next course of action be to trace those wires back? They are neatly bundled with other wires, and look to be factory so I haven't undone that yet. Maybe the cut wire the installer needed is tucked back in that. It's a puzzle and it'll get solved but I'm moving more cautiously now. My fear is missing a connection and somehow causing more damage during the first test (which is not even close).
Is it possible no wires were interrupted somehow and I'm over thinking this (I don't think so but I over-think)?
18, two wires are cut closely behind this
Cut wires approx behind 18
Ignition switch socket
Swag/removed wires
Control unit
Wires to valet switch |
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space_out_today Samba Member
Joined: February 13, 2017 Posts: 21 Location: Southern California
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Posted: Sun Jun 22, 2025 7:50 pm Post subject: Re: Hornet 723T security system de-installation advice |
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I've removed the security system..
My last post was a bit of a "yard sale" of information and pictures, and admittedly, I was pretty concerned about the next steps.
If nothing else, this project forced me to refamiliarize myself with the wiring diagrams and conduct some testing I hadn't done before.
It turned out that the schematic was right – there was one broken connection, and it was tucked up in the wire harness under the instrument cluster. I removed and/or reterminated quite a few splices and pigtails.
Once that was discovered, I continuity tested as much as I could. I was still a bit concerned about connecting the battery and energizing everything, but it started right up! I still need to go through and validate all the other electrical consumers (lights, etc.), but so far, it looks good.
Thanks for the Hornet installation manual. I wouldn't have felt comfortable without it and probably would have kicked this down the road for another 1-3 years.
Much appreciated—this was a very gratifying project to complete. |
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