SOLVED!! 1986 R80RT low beam / turn signals /horn not working- Airhead newbie :)

[tallcanuck]

New owner and not super mechanical so I’m hoping the community can point me in the right direction.
1986 R80 RT.
Bought it three days ago and rode it three hours home.
All electrical worked when I bought it.

When I got home low beam not working/ left and right signals not working and horn not working.
High beam not working but highbeam flash does
Brake light works fine.
Parking light works fine.

I replaced the two white eight amp fuses under the seat With no difference.
I looked inside the headlight and there are no fuses in there.
Any other fuses anywhere?
Bike starts fine.

OK, I’m at your mercy.
Can you teach the newbie what to look for to fix this please?
Thank you from a new airhead owner!!

 

[stevenrankin]

Had the bike been sitting for a while? What condition is it in, what is the mileage? I ask because you problem may just be a matter of dirty connections and such.
The headlight is not fused, locate the headlight relay and check to see if the pins on it and the socket are clean. Headlight relays are most times the first thing to go rather than the handlebar switch. Of course check the bulb as well. LOL.
Same goes for the turn signals, find the flasher unit and check it as well. LOL, I just had the same issue on my RT with intermittent turn signals, it seems the flasher unit came loose in the socket and would or would not make contact. Unlike your bike, all my "stuff" is in the headlight shell. While most of yours is under the gas tank.
The horns may be just a ground issue, Check with a test probe to see if you have voltage to them, if you do clean up the mountings and try again.

Age and corrosion with riding in wet conditions cause a lot of issues over 38 years, since I can't see the bike you have, this is the best I can do for now.
There is a product heavily touted by one of the guys on the airhead forum called No-Ox, he claims it cures everything electrical. I use it but can't make his claims, lol.

Buy yourself a good wiring schematic from EME company, if you are going to work on the bike, it is best to have as many different schematics as possible for that year and model. EME's units are large, color, matted, and have plug and PIN numbers on them. Good luck, St.

 

[20774]

The horn circuit is pretty simple relatively speaking. Find an electrical diagram and trace it. What little I can tell is that the ground for the horn goes through some kind of junction/connection plug which then connects the horn, turn signals switches. Maybe those connectors have become corroded and need to be cleaned.

 

[stevenrankin]

Interesting note Kurt, on my 84 RT, the horns are grounded to the frame. The only line in is positive power. Since I didn't look at a schematic for an 86, it could be things changed.

After a recent rebuild, it took me a bit of time to grind off enough powder coating to make a good ground and get a nice two horn beep. St.

 

[tallcanuck]

Wow, thank you for the responses. This is fantastic!!!!!

Yes it was sitting for a while. Mileage low 27,000km.
The previous owner did not ride it much so I think it was sitting in his garage for a year or two.

You may be right about dirty connections.
I will start there
I will order myself a good wiring schematic from EME as well as the No ox product as well as a test probe to start testing things.

Super newbie question—
If I need to get under the gas tank, how difficult is that to lift or remove?
Can I just turn the petcocks off and lift the tank or do I need to drain tank, disconnect the gas lines to lift the tank or remove it?
Again sorry for the super basic questions and thank you all for your help!!!!!

 

[omega man]

With this forum software, spelling is quick to be “changed”.
There is a possibility that the No ox is either-
Noalox- https://www.idealind.com/us/en/category/product.html/noaloxr-noalox.html
Or- DeoxIT- https://caig.com/deoxit-d-series/

Either product is helpful…. Just in case.

OM

 

[stevenrankin]

Unless they made super major changes in 86 versus 84, you need to close the petcocks, no need to drain the tank, LOL, as long as they are working properly, you will find out pretty quick about that. Remove the two lines on the petcocks and look in the middle bottom of the tank, there may be another hose hooked up that is used as an overflow drain for the tank cap area. No gas there, should be no clamp or fitting. Pull that off. Undo the two thumb nuts at the back of the tank and it should lift back, up and off. It is supported in the front by a bushing on the frame. most of the relays and such will be on the left side of the frame. Good luck, St.

 

[tallcanuck]

Apologies for newbie questions and Thank you!!!!!!!!!!!!

 

[spearman79]

On my 1986 K75T, I had to replace the combination switch.

 

[tallcanuck]

Thanks I did not think of that!!

 

[dduelin]

My 1981 R100 had a plastic connector in the wire harness that ran along the upper left sub frame rail in the area of where the rear sub frame bolted to the frame. The connector allowed the sub frame to be removed without cutting the wire harness. This connector was located just about where the back of the gas tank is. The seat had to be removed to access the connector - I don't remember having to remove the tank but as detailed above it's not difficult to remove the tank if need be. A bit of corrosion in that connector faulted the turn signals, brake/tail light and horn IIRC on my bike. The horn for sure. The 1986 R80RT and '81 R100 are closely related.

 

[tallcanuck]

Thanks dduelin!!

 

[88bmwjeff]

With regards to the horn, have you tested the horns by direct connecting them to a battery? My 88 RT sat for 5-6 years and one of the horns froze up. Thinking I had nothing to lose, I tapped it moderately hard with a rubber mallet which did the trick. In any case, it would be good to eliminate the horns as being the issue.

 

[tallcanuck]

Thanks, Jeff good idea!!

 

[AntonLargiader]

Flash-to-pass and horn are powered by the same wire to the switch, so if one works and one dosn't then it's happening after that point. I'd start by just unplugging and re-plugging the two connectors for the left switch, usually under the tank at the front. Wouldn't hurt to spray some contact cleaner into the switch assembly, too. Start with the basics.

Checking the voltages coming out of the witch is probably the most efficient way to go, if you are up for it. I list the switch connections on this page: https://largiader.com/articles/euroswitch/

 

[tallcanuck]

Thank you Anton !!

 

[tallcanuck]

Solved!!!!! Thank you all for your help to this newbie. I pulled the gas tank off and a connection under the tank had become unplugged. Cleaned it with electrical cleaner plugged it back in and everything is working. Thank you all for your help. Truly appreciated.

 

[20774]

Thanks for filling us in with your success!!

 

[stevenrankin]

LOL, my favorite kind of repair. Thanks for the update it is appreciated. St.