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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: JD! on July 15, 2022, 02:27:54 AM

Title: K75RT Electrical Help
Post by: JD! on July 15, 2022, 02:27:54 AM
Hi,
I have a 1993 K75RT that the previous owner clipped all the leads short when he discarded the front fairing.

I'm a shite electrician and need help ID'ing a pair of leads. They come off the loom along with the leads to the left blinker.

From what I can tell squinting at my Clymer's, the leads (green/blue (G/L), and brown) are part of the bulb monitoring system. They don't seem to show any voltage when the ignition is on.

I'm going to run aftermarket lights, so do I need to do something with the mystery leads?

Cheers
Jim


Title: Re: K75RT Electrical Help
Post by: The Mighty Gryphon on July 15, 2022, 07:06:08 AM
As far as I know, the K75RT only has two horns, two turn signals, a head light and parking light in the fairing.  If your headlight, parking light and turn signals work, the remaining wires probably go to a horn that may have been removed by the previous owner.
Title: Re: K75RT Electrical Help
Post by: frankenduck on July 15, 2022, 10:39:21 AM
Here's the Clymer wiring for the BMU. It has no green/blue wires.

(https://i.imgur.com/7FKnhpY.jpg)


On a stock K75:

Green/blue wires come from the load shed relay and provide lighting power to the right combination switch (headlight/parking light switch) and left combination switch(flash to pass) as well as power to the #7 fuse. The #7 fuse sends power to the following via green/brown wires:
Flasher relay
Alarm connector
Horn relay
Thermo relay (for radiator fan)

There is no green/blue wire that goes directly to any of the lights. (or horn)

All brown wires are ground.


Title: Re: K75RT Electrical Help
Post by: Laitch on July 15, 2022, 02:29:51 PM
Here are schematic color renditions from Clymer for 1990 and on. You might be looking at the flasher unit because it is depicted in the unit's diagram below as having a G/B wire. The turn signals aren't part of the bulb monitoring scheme.
Title: Re: K75RT Electrical Help
Post by: JD! on July 15, 2022, 06:26:27 PM
As far as I know, the K75RT only has two horns, two turn signals, a head light and parking light in the fairing.  If your headlight, parking light and turn signals work, the remaining wires probably go to a horn that may have been removed by the previous owner.

Bingo! Looking at the somewhat faded wires, my mystery lead has the same colours as the known horn lead, G/GR, not light blue as I thought at first.

Voltmeter confirms voltage when horn button is activated.

One confusing thing is the remaining horn was mounted on the frame, near the radiator on the right side. I didn't realize that there should have been two horns. Another PO kluge, evidently.

Thanks for the help.

Jim
Title: Re: K75RT Electrical Help
Post by: The Mighty Gryphon on July 15, 2022, 10:14:43 PM
You're welcome!  Glad you got it figured out.
Title: Re: K75RT Electrical Help
Post by: JD! on July 16, 2022, 07:04:04 PM
Here are schematic color renditions from Clymer for 1990 and on. You might be looking at the flasher unit because it is depicted in the unit's diagram below as having a G/B wire. The turn signals aren't part of the bulb monitoring scheme.

Any link to the schematic in colour? My Clymer is black and white.

Thanks
Jim
Title: Re: K75RT Electrical Help
Post by: rbm on July 17, 2022, 01:46:10 AM
Any link to the schematic in colour? My Clymer is black and white.

Thanks
Jim
Try this link from my Google Drive:
https://drive.google.com/file/d/0B3UPbNZRyr1raHpPeUpUeGkxM2M/view?usp=sharing&resourcekey=0-z22TceR1coe9t0c54qQeYg
Title: Re: K75RT Electrical Help
Post by: JD! on July 19, 2022, 11:26:53 PM
Try this link from my Google Drive:
https://drive.google.com/file/d/0B3UPbNZRyr1raHpPeUpUeGkxM2M/view?usp=sharing&resourcekey=0-z22TceR1coe9t0c54qQeYg

Downloaded a copy. Many thanks! It will be a valuable document during the project.

Cheers
Jim