Turn signal being weird.

[ColumbiaBMW]

Hey everyone,
I can only do simple things like change oil, brake pads, air filter, etc. So when it comes to a weird electronic issue, I am completely lost. My left turn signal will blink fine for a few seconds, then blink fast. I thought at first one of the bulbs must be going out, but then I noticed that both bulbs are fine, and they both blink fast when it starts messing up. It's very random though, it will blink fine at times, then fast, then back to normal, with no pattern. So I'm assuming it is something with the wiring. Should I just take it to the BMW guy here in town and have him take a look, or is there something fairly easy that I can try first. Thanks for any advice you can offer.

Bryan

[NoRRmad]

The first thing I'd try is to replace the flasher unit, in the electrics box under the seat. The rightmost black box in the same row as the fuses, I think. It takes some finagling to get it out, tabs to press while pulling up, and a strange electrical connection with a swingover lever to lock it closed, but just a minute's work for a tech who knows the way.

Might be time to get a Kisan Signalminder -- which is a direct plug-in replacement, and has features you might like.

[CycleRob]

Bryan,

Make the easy shots first. Left side only failure tells me it's unlikely the flasher unit.

Remove both left side lenses and remove each bulb to clean the bulb end solder terminals. They corrode with age and water exposure, loosing the good electrical contact they need. One bulb won't flash and the flash rate will then go very fast with the current load halved. If you didn't notice it not flashing, then it's likely the rear one. Sandpaper is too harsh, so clean them up on your old dungarees . . . . the thigh section works great. A few foot long hard drags should shine them pretty good. Then look inside the sockets and scrape them clean with a small screwdriver, where ever you see corrosion fuzz or powdery deposits.

The next possibility is a broken wire in the wire harness that bends when the handlebars are turned.

To test which one it is at fault, remove both left signal lenses, then:
--Killswitch off, both the ignition key and left signal ON.
--Turn/wiggle each signal bulb to prompt the previous failure.
--Very slowly, turn the handlebars full left and full right watching both signal flashes. If there's no change, slowly move/relocate the front wire harnesses to reveal the wire breakage point.

.

[bikermeow]

My bet is on broken wire. Try this for diagnosis; put the beast on the centrestand, and play about with the signals while turning the handle to both extremes.

Cheers

[Arbee]

condensation or water ingress does funny things to electrics especially
if it takes a long time to dry out do as Cyclerob suggests, what i normally
do is scratch the indicator globe gently across some concrete to remove
the lead oxide on the terminal.

[ColumbiaBMW]

Last night I took the signals apart, cleaned them off, checked for any broken wires but they looked good, and then put the signals back together and it still is acting up. It will blink fine for a while, then blink fast, then go back to normal...then back to fast, etc. Both bulbs are working fine though, and they both blink fast together, so I don't think it's a problem with the bulbs, or one of them wouldn't be blinking at all, and I don't think it's the flasher unit because it only happens to the left side. Also, I played with all the wires, and turned the bars to see if that made a difference, nothing seemed to matter, it appears to be completely random.

I'll take the tank off tonight and check all of the wires, but it looks as though I'll be taking it to the dealership, and then tell my son we can't afford to send him to college when he's older because daddy wants to ride a BMW. (If my wife sees this, I'm just kidding!)

[CycleRob]

Here's another easy shot. Swap the left and right signal bulbs with each other. Try flash test again. If that fails, then the complex signal flasher unit is the last villain and credit goes to NoRRmad for the diagnosis.The one big problem is the cash required replacing that unit. The Kisan Signalminder Craig recommended really is a better replacement too, lessening the pain of spending the kids college funds.

Checking the wiring diagram, there are almost a dozen wires emanating from that unit. Unlike the single switch 3 terminal flasher unit, the left/right switching is made inside the flasher unit -not- in the handlebar signal switch itself and why the usual open/short flaws may not change the flash rate.

[rich1kim]

Hey, my bike did the same thing. I just changed all the bulbs even if they looked fine and now it's ok. Bulbs aren't too expensive.

Rich