Author Topic: 92 K75 RT alarm removal / bypass  (Read 5186 times)

Offline DavidATL

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92 K75 RT alarm removal / bypass
« on: September 25, 2016, 02:33:33 PM »
I want this gone! The horn blips occasionally when I turn the bike off and this morning started repeatedly going on/off once I was back from an early day ride. Not cool when the kids are sleeping in...

Before I start plowing through wiring diagrams, I thought  I consult the internet. Unfortunately, I found very little info on defeating or removing the system ... so I thought I'd consult the experts. (that would be you folks).

description:
The bike appears to have an OEM alarm unit (dealer installed probably) with a two button remote fob. Not sure if there are multiple versions of the alarm so here is a brief description. This one has two modules. One appears to be a main control module ( labeled BMW on the top) and has a white flat, two x  six (11 pins, one blank) pin connector. The other module is smaller, with a single wire, and is labeled "BMW logicsensor." Unplugging the main unit results in power on / no crank condition (dash lights up, when the start switch is depressed the fuel pump comes on but the starter does not turn).

I'd like to remove the main unit (the body wiring can stay) and jumper pins on the white bodyside connector as needed.

Would someone please point me toward some information related to defeating / removing / bypassing the main alarm control module? Thanks!


  • Atlanta
  • K75RT '92 w/ 28k miles (former bikes: '82 FT500, 80's GL500 Silverwing, 550 Nighthawk and FINALLY an '88 K75S) https://georgiaroads.wordpress.com including my #GA4corners route

Offline K1300S

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Re: 92 K75 RT alarm removal / bypass
« Reply #1 on: September 25, 2016, 02:46:49 PM »
Just unplug it at the fuse box connector?
Project Thread "K75s Midlife Refresh"
http://www.motobrick.com/index.php/topic,7810.0.html

Offline Inge K.

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Re: 92 K75 RT alarm removal / bypass
« Reply #2 on: September 25, 2016, 07:41:44 PM »
It sounds like you have a alarm for a later model ....but if it's only the starter signal that is via the
imobilizer.....I would have started with a look on the starter relay which you find in the relay box
under the rear end of the tank.
The starter relay is in the rear RHS corner and and have two screw terminals and a white connector
for the signal wires.....follow these signal wires, then I'll guess that it would be obvious which contacts
you have to bridge at the control unit end......or reverse connections to pre alarm mounting.
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Offline D.Bachtel

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Re: 92 K75 RT alarm removal / bypass
« Reply #3 on: September 25, 2016, 08:04:45 PM »
"Just cut the red wire."

"But they're all red wires!"


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Offline kioolt

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Re: 92 K75 RT alarm removal / bypass
« Reply #4 on: September 25, 2016, 09:02:44 PM »
Another option would be to find the wire on your alarm that is beeping you horn and cut it.  That way the alarm will become an imobiliser giving you some protection without the horn.
2018 R1200RT 8,000 miles,2004 R1150RT 189,000 miles
1991 K100LT 128,700 miles,1982 R100RT 106,900 miles
The cheapest thing on a BMW is the nut that connects the seat to the handlebars.

Offline Martin

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Re: 92 K75 RT alarm removal / bypass
« Reply #5 on: September 25, 2016, 09:19:03 PM »
+1 Kioolt
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Offline Inge K.

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Re: 92 K75 RT alarm removal / bypass
« Reply #6 on: September 26, 2016, 02:09:08 AM »
Another option would be to find the wire on your alarm that is beeping you horn and cut it. 

On the first generation OEM alarm it was a built in siren in the main control unit that was activated if the
wires to the horns where cutted.
I would expect that this one also have that function.
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Offline DavidATL

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Re: 92 K75 RT alarm removal / bypass
« Reply #7 on: September 28, 2016, 08:37:51 AM »
Thanks for all the comments. I rummaged through the documentation I have from previous owners and found the alarm installation manual and pinout diagram (attached)

Looks like pin 10 and 12 are an interrupt to the starter relay control. I unplugged connector from the main control box and put a jumper across the bodyside connector pins 10 and 12. The bike starts and operates fine.

  • Atlanta
  • K75RT '92 w/ 28k miles (former bikes: '82 FT500, 80's GL500 Silverwing, 550 Nighthawk and FINALLY an '88 K75S) https://georgiaroads.wordpress.com including my #GA4corners route

Offline Inge K.

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Re: 92 K75 RT alarm removal / bypass
« Reply #8 on: September 28, 2016, 08:44:39 AM »
Would be Nice With a Picture of main Control unit.  :yes
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Offline DavidATL

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Re: 92 K75 RT alarm removal / bypass
« Reply #9 on: September 28, 2016, 08:53:42 AM »
Main control unit is part number 95 00 5 000 100. See attached pics including TEMPORARY jumper. :-)

The smaller module hard wired into the main control unit is the 'BMW logicsensor" Sounds as if there is liquid in side - a mercury switch perhaps?
  • Atlanta
  • K75RT '92 w/ 28k miles (former bikes: '82 FT500, 80's GL500 Silverwing, 550 Nighthawk and FINALLY an '88 K75S) https://georgiaroads.wordpress.com including my #GA4corners route

Offline Inge K.

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Re: 92 K75 RT alarm removal / bypass
« Reply #10 on: September 28, 2016, 08:57:34 AM »
Thanks  :clap:
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Offline Inge K.

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Re: 92 K75 RT alarm removal / bypass
« Reply #11 on: September 28, 2016, 09:20:47 AM »
Seems like a universal model...found the price in BMW's system...no info about which models.
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Offline DavidATL

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Re: 92 K75 RT alarm removal / bypass
« Reply #12 on: September 28, 2016, 09:27:07 AM »
Does seem to be a universal module. The body wiring harness is specific to the bike.

I only found two mentions of the control module part number on the net:

from May, 2006:
http://www.ukgser.com/forums/archive/index.php/t-73978.html
under   ::. UKGSer .:: > The Bikes > BMW > 850/1100/1150 Oilheads > Alarm info needed

and

from Feb, 2011:
http://www.k11og.org/forum/viewtopic.php?t=10045&view=previous&sid=0e2182a2bf5b96de8d905ad000052eb1
where it was installed on a 1994 K1100LT.

I found this link to better installation instructions but the part number for the K-bike harness looks to be wrong:
http://www.ibmwr.org/ktech/alarm-install.shtml

"long harness (part number 95 00 5 000 120)" - per the instruction manual, this is the short harness number. The long number is 95 00 5 000 110 per the installation guide.

The main control module and logic sensor were mounted in the box below the seat on my K75RT.

  • Atlanta
  • K75RT '92 w/ 28k miles (former bikes: '82 FT500, 80's GL500 Silverwing, 550 Nighthawk and FINALLY an '88 K75S) https://georgiaroads.wordpress.com including my #GA4corners route

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