1995 R1100RSL horn and turn signals quit working at the same time

[hbwallace]

Going for a ride yesterday I attempted to honk at a neighbor boy and after a very abbreviated honk from my twin Hella horns, they went quiet. A block away I put the right turn signal on and I think it temporarily made a flash then nothing. When I started the bike the emergency flashers were on. I turned them off before riding.
So far I have checked all fuses which were ok. Swapped relays with negative results. Checked horn connections which were ok.
Does anybody know what is the common denominator between turn signals and horn that might have caused this. I did pull and reinstall the flasher unit also. I’m guessing a wire loom problem maybe. The bike has 136000 miles on it and is otherwise in great shape.
Any assistance will be appreciated. My diagnostic skills are limited.
Bruce Wallace

 

[BC1100S]

Beyond checking the fuses you might try simply changing out the old one for a known good one.

 

[6322]

Going for a ride yesterday I attempted to honk at a neighbor boy and after a very abbreviated honk from my twin Hella horns, they went quiet. A block away I put the right turn signal on and I think it temporarily made a flash then nothing. When I started the bike the emergency flashers were on. I turned them off before riding.
So far I have checked all fuses which were ok. Swapped relays with negative results. Checked horn connections which were ok.
Does anybody know what is the common denominator between turn signals and horn that might have caused this. I did pull and reinstall the flasher unit also. I’m guessing a wire loom problem maybe. The bike has 136000 miles on it and is otherwise in great shape.
Any assistance will be appreciated. My diagnostic skills are limited.
Bruce Wallace

You might start with checking your ground wires and make sure the contacts are clean and tight.

 

[m_stock10506]

Going for a ride yesterday I attempted to honk at a neighbor boy and after a very abbreviated honk from my twin Hella horns, they went quiet. A block away I put the right turn signal on and I think it temporarily made a flash then nothing. When I started the bike the emergency flashers were on. I turned them off before riding.
So far I have checked all fuses which were ok. ...........................
Bruce Wallace

Looking at the fuse box diagram for the 1100RT, fuse 4 controls turn signals, hazards, horn and relay 5 - horn relay. Fuse 4 is a 15A fuse. You say you checked all fuses. Visual inspection or with a voltmeter or test light. Visual inspection can be very misleading. Try swapping fuse 4 with a new fuse, or with one of the other 15A fuses. On the RT diagram, all of the other fuses are for critical circuits, swap for a new 15A is probably best. Fuse 4 is only powered when the ignition is on.

 

[skibum69]

The clock and horn going on my 1100S turned out to be a fuse.

 

[pglaves]

Well, both the horn and turn signals are on fuse 4. And both the horn and signals seem to have worked for an instant but then not worked. This is not blown fuse behavior but it is bad fuse connection behavior. If the connection in the fuse holder is bad and won't carry much current it still might test good with a volt meter and the fuse would visually look OK. The bad connection might be in the fuse holder. It also might be internal to the fuse. I would remove the fuse and throw it away even if it seemed to test OK. Then I would use electrical cleaner to clean the socket. Then I would insert and remove the new fuse several times to ensure a good contact.

 

[hbwallace]

Well, both the horn and turn signals are on fuse 4. And both the horn and signals seem to have worked for an instant but then not worked. This is not blown fuse behavior but it is bad fuse connection behavior. If the connection in the fuse holder is bad and won't carry much current it still might test good with a volt meter and the fuse would visually look OK. The bad connection might be in the fuse holder. It also might be internal to the fuse. I would remove the fuse and throw it away even if it seemed to test OK. Then I would use electrical cleaner to clean the socket. Then I would insert and remove the new fuse several times to ensure a good contact.

Thank you all and especially you paul. After removing Tupperware and twisting wire looms with negative results, while holding the horn button down I smacked the fuse box and the horn briefly honked. I replaced all fuses which had checked out ok and now all is well. After 25 years and 136000 miles I guess even good fuses go bad! The previous remark about replacing the fuse even if it checked out was also right on.
Thank you all. Riding tomorrow
Bruce in Toquerville Ut

 

[chrisinsc]

My 99 1100rt has an aftermarket horn and it would blow the fuse if I ran it for two seconds. Maybe it's old. I sprayed lube everywhere I could in the horn compressor but eventually I put a fuse with a higher value in the slot. Losing my turn signal/hazards/flashing stoplights was too big a price to pay. Would rather have the horn fail.

 

[52184]

My 99 1100rt has an aftermarket horn and it would blow the fuse if I ran it for two seconds. Maybe it's old. I sprayed lube everywhere I could in the horn compressor but eventually I put a fuse with a higher value in the slot. Losing my turn signal/hazards/flashing stoplights was too big a price to pay. Would rather have the horn fail.

Installing a higher-capacity fuse means that the overload from your aftermarket horn can damage or destroy the wires in the horn circuit, which are not that robust to begin with on the oilheads. The real solution is to install a relay, triggered by the OEM horn circuit, with the power feed for the horn coming directly from the battery. That gives you both a louder horn and protection against overloading and burning up the horn wiring circuit. Just sayin’...

Best,
DeVern

 

[chrisinsc]

Installing a higher-capacity fuse means that the overload from your aftermarket horn can damage or destroy the wires in the horn circuit, which are not that robust to begin with on the oilheads. The real solution is to install a relay, triggered by the OEM horn circuit, with the power feed for the horn coming directly from the battery. That gives you both a louder horn and protection against overloading and burning up the horn wiring circuit. Just sayin’...

Best,
DeVern

Indeed. A total hack short term fix on my part

 

[BC1100S]

Indeed. A total hack short term fix on my part

Should have just wrapped the old fuse in tinfoil.

 

[pglaves]

I recommend that this horn not be used until; A) proper wiring and a relay are installed; or B) you have a replacement wiring harness to be installed after you need to use a fire extinguisher.

 

[chrisinsc]

I recommend that this horn not be used until; A) proper wiring and a relay are installed; or B) you have a replacement wiring harness to be installed after you need to use a fire extinguisher.

That horse left the barn over a year ago! I never run it for more than a few seconds but you are all right to point out that the BMW engineers may not have designed that circuit with a 2x safety factor in the wiring

 

[pglaves]

That horse left the barn over a year ago! I never run it for more than a few seconds but you are all right to point out that the BMW engineers may not have designed that circuit with a 2x safety factor in the wiring

I think it is OK for a stock pair of horns. But those compressor type air horns pull a bunch of amps. I had one melt a wire on a used jeep I bought. Luckily it was a lone 12v+ wire and not in a harness.

 

[chrisinsc]

Should have just wrapped the old fuse in tinfoil.

You have to draw the line somewhere!

 

[chrisinsc]

I think it is OK for a stock pair of horns. But those compressor type air horns pull a bunch of amps. I had one melt a wire on a used jeep I bought. Luckily it was a lone 12v+ wire and not in a harness.

I truly appreciate the concern. It did not begin blowing fuses until I installed the Kisan sm-5 hazard, brake light, and turn signal unit. I just assumed that the combo of that aftermarket unit along with the horn was overloading the fuse and the main point of concern was the wire from the fuse to the battery. The relay for the horn is just a better answer and should have been done when the horn was installed.

 

[eastbay]

Should have just wrapped the old fuse in tinfoil.

I remember reading about a guy who used a handy 22 round in place of one of those old VW fuses. He was a recipient of the Darwin Award.