Results 1 to 7 of 7

Thread: electrical connection gremlin in 1980 R100RT

  1. #1
    Registered User mysteriousfish's Avatar
    Join Date
    Feb 2011
    Location
    Portland, Oregon
    Posts
    94

    electrical connection gremlin in 1980 R100RT

    A couple of months ago I started having a very sporadic electrical gremlin pop up then go away...the instrument background lights, front parking light and tail running light would not come on upon engine start up. Turn signals, headlight and brakelight would still work. Sometimes all it took was to turn off and restart the bike and they would come back on...other times, they would come on within a few minutes of riding the bike. Have not ridden much at night, so was a low priority as I worked on (and enjoyed riding) my 91 R100 cafe project. Of course, Mr. Murphy's Law of bad outcomes kicked in as I ended up riding home after dark from LaGrande to Portland yesterday, and the lights would not on. Luckily, my Remington LED flashlight has an intense red light setting, and I bungied it to my rear rack, creating an effective rear running light (Mr. John Law passed me without slowing down, so it served its purpose to get me home). Of course, when I stopped for gas when almost home, my instruments and taillight came back on!

    I assume I have a loose connection somewhere, maybe in the ignition switch (the instrument, front parking and taillights work when the ignition switch is in the middle parking light mode). Before I start checking connections, wanted to see if anyone had experience this particular problem or had advice on where to start diagnosing? many thanks!
    michael
    __________
    1991 R100 classic; 1980 R100RT

  2. #2
    Registered User
    Join Date
    Feb 2013
    Posts
    139
    Here's what it turned out to be when this happened to me. The headlight wires, when stuffed back into the headlight shell, were sometimes putting a bit of pressure on the fuse holder in the back of the headlight shell and causing reduced pressure between the holder and the fuse. This would cause an intermittent failure in my turn signals and tail lights and similar problems with the dash lights. There are two fuses. I installed an "inline" fuse holder to replace the top fuse and have not had the problem since. I don't know if your headlight shell is set up the same (I have a 1976 R75/6) but it was a bear tracking this problem down.

    Chip

  3. #3
    Registered User mysteriousfish's Avatar
    Join Date
    Feb 2011
    Location
    Portland, Oregon
    Posts
    94
    Quote Originally Posted by cseltz View Post
    Here's what it turned out to be when this happened to me. The headlight wires, when stuffed back into the headlight shell, were sometimes putting a bit of pressure on the fuse holder in the back of the headlight shell and causing reduced pressure between the holder and the fuse. This would cause an intermittent failure in my turn signals and tail lights and similar problems with the dash lights. There are two fuses. I installed an "inline" fuse holder to replace the top fuse and have not had the problem since. I don't know if your headlight shell is set up the same (I have a 1976 R75/6) but it was a bear tracking this problem down.Chip
    Thanks for the heads up regarding possible fuse holder connections...was looking at the wiring diagram in my Clymers and it looks like that could be my issue, too...

    sheepish question: where is that pesky fuse holder on a 1980 R100RT? The manual says it is under the seat and toolkit tray, but I do not find it there. My 91 R100 has the fuse box under the rear lip of the tank, tucked in under the end of the top tube member...but it is not there on the 1980. I don't think it is in the headlight bucket, as it looks like a PITA to get the fairing lens cover off. I suppose the PO could have moved it/modified it, as lit looks like there were some accessory connections that are no longer being used. Have not had a chance to pull the tank off yet and look there. Feeling pretty stupid..seems like it should be right there...
    michael
    __________
    1991 R100 classic; 1980 R100RT

  4. #4
    Registered User
    Join Date
    Feb 2013
    Posts
    139
    The 80 R100RT is likely different from mine. The fuse holders are a part of the circuit board attached to the back of the headlight shell on my bike.

  5. #5
    Vern 12907's Avatar
    Join Date
    May 2006
    Location
    Somewhere In The Swamps of Jersey
    Posts
    63
    Quote Originally Posted by mysteriousfish View Post
    I don't think it is in the headlight bucket
    In the PITA headlight bucket......
    Have fun & Ride safe, Anthony
    '83 R100RS
    '03 GL1800A
    '99 KLR 250

  6. #6
    Registered User
    Join Date
    Feb 2013
    Posts
    139
    What some PO had done with mine was add a substantial length of wire (4 wires total) to the connector for the headlight so that you could take the headlight out and rest it on the fender without disconnecting. This bundle of wires, when I stuffed it back in was occasionally pushing against the "high" side of the fuse holder. I bought an in line fuse holder from Pep Boys, disconnected the line and load connectors from the circuit board and reconnected them through the in line fuse holder.

  7. #7
    Jim Carr
    Join Date
    Aug 2011
    Location
    Loleta CA
    Posts
    20
    On my 83 R100RS the fuses are in the headlight bucket. It's not that hard to get in. A small Phillips in each corner behind the weather seal and the headlight tunnel comes out, then a Phillips at the bottom of the headlight and your in.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •