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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Miltonk1100 on January 03, 2021, 06:00:23 PM

Title: '95 K1100LT - engine stalls when fan relay activates
Post by: Miltonk1100 on January 03, 2021, 06:00:23 PM

Just purchased new project so not sure what has been done. Appears ABS has been removed.
Issue: Engine starts and warms up nicely until fan relay kicks in, which instantly kills engine.
Looking at the relays I see a jumper from the violet/yellow of the fan relay to the Brown/Blue of the Motonic relay. Won't start if I disconnect this jumper.

Any ideas?

Title: Re: '95 K1100LT - engine stalls when fan relay activates
Post by: Scott_ on January 03, 2021, 08:35:24 PM

The brown/blue wire is the 'ground' circuit for the motronic relay. It goes thru the side stand switch for ground, to energize the motronic relay.
If you say the bike won't start with this jumper removed, check the wiring to the side stand switch. BR/BL to the switch and then BR from the switch to a ground point.
BTW the bike isn't intended to start with the side stand down.
If you say the bike dies when the fan relay energizes, that makes sense to me. As the fan relay closes it puts equal +12 on the BR/BL wire, 'over powering' the 'weak ground' thru the fan motor wiring to the motronic relay.

Title: Re: '95 K1100LT - engine stalls when fan relay activates
Post by: Miltonk1100 on January 03, 2021, 10:17:19 PM

OK, that makes sense. So to do a quick test I could just remove the jumper from the fan relay and then ground the brown/blue to simulate the side stand switch being closed. ...and if that works, then my issue is the side stand switch if I read that correctly. I've got a few months until Spring arrives in Canada so may as well get it ready :-)

Title: Re: '95 K1100LT - engine stalls when fan relay activates
Post by: Scott_ on January 04, 2021, 05:29:32 AM

Quote from: Miltonk1100 on January 03, 2021, 10:17:19 PM

OK, that makes sense. So to do a quick test I could just remove the jumper from the fan relay and then ground the brown/blue to simulate the side stand switch being closed. ...and if that works, then my issue is the side stand switch if I read that correctly. I've got a few months until Spring arrives in Canada so may as well get it ready :-)

Yes, that would be correct.
You can also test to make sure your fan motor is good as well.

Title: Re: '95 K1100LT - engine stalls when fan relay activates
Post by: Miltonk1100 on January 04, 2021, 06:38:40 PM

You are an absolute genius!  I removed the jumper, grounded the blue/brown and everything operates as it should.
Thanks for all your help :-)