I need a colored wiring diagram - 1989 R100RT

[gspd]

On my handlebar I only have high-beams (on/off, not even flashing)

'Flash-to-pass' function.
When you push down the high beam should go on, when you release it the switch should spring back to the center position.
Maybe yours needs a bit of lubrication.

FYI-
The 'non-euro' swtch has plastic detent bumps for the turn signal switch that tend to eventually wear out making it difficult to firmly 'click' the turn signal back to it's exact center (off) position without looking.
The 'euro' switch has metal bumps that don't wear out.

[Mallo81]

On my handlebar I only have high-beams (on/off, not even flashing)

'Flash-to-pass' function.
When you push down the high beam should go on, when you release it the switch should spring back to the center position.
Maybe yours needs a bit of lubrication.

FYI-
The 'non-euro' swtch has plastic detent bumps for the turn signal switch that tend to eventually wear out making it difficult to firmly 'click' the turn signal back to it's exact center (off) position without looking.
The 'euro' switch has metal bumps that don't wear out.

Got it, that can be. Thank you. The high beam / flashing is not really a problem here for me.
But where is the light-dimmer switch here? The one that shows in the diagram? I don’t have it, I just turn the key..

[gspd]

But where is the light-dimmer switch here? The one that shows in the diagram? I don’t have it, I just turn the key..

With your type of switch, turning the key to position 1 should activate only the parking lights; 3w bulb in (or on top of) headlight + the tail light bulb. Key can be removed. This is so you can leave your illuminated bike parked and watch the battery go dead.

Turning the key to position 2 should activate the ignition and headlight. Key cannot be removed.

Your bike's wiring may have been modified by previous owner(s). (possibly when the left handlebar switch was replaced?)

Where's RobF when you need him?

[Mallo81]

But where is the light-dimmer switch here? The one that shows in the diagram? I don’t have it, I just turn the key..

With your type of switch, turning the key to position 1 should activate only the parking lights; 3w bulb in (or on top of) headlight + the tail light bulb. Key can be removed. This is so you can leave your illuminated bike parked and watch the battery go dead.

Turning the key to position 2 should activate the ignition and headlight. Key cannot be removed.

Your bike's wiring may have been modified by previous owner(s). (possibly when the left handlebar switch was replaced?)

The wiring is original, never been modified.. I will figure out, it is not too complicated at the end.. it’s just annoying that the wiring diagram is off.. all good, some good night practice with wires and multimeter ahead!

[melville]

Indeed, she's always on her best behaviour! We got out yesterday and she likes the backrest mods for more room although I'm kinda missing the forced spooning.

My 1975 /6 has a headlight switch and probably had it from the start.

My 1978 /7 does not have a headlight switch. I believe 1978 was the year always-on became a US requirement.

After 40+ years, the headlight switch on the /6 was getting dodgy about keeping contact, so I rewired the bike for 'always-on' headlight. All the wires I needed were already there in the harness. I reasonably expect this was still the case on your RT, as this would keep BMW from having to make different main harnesses for different markets. So if you were to get a Euro switch, it's probably plug-n-play.

[Rob Frankham]

If you look at the second diagram above, you will see that the lighting switch is marked 'UK models' (should really be Euro models really) and a link on the multiple plug is marked 'US models' That means those items are only present in the designated territory. The switch shown in GSPDs other post is standard for most European models...

Rob

[gspd]

..so I rewired the bike for 'always-on' headlight. All the wires I needed were already there in the harness. I reasonably expect this was still the case on your RT, as this would keep BMW from having to make different main harnesses for different markets. So if you were to get a Euro switch, it's probably plug-n-play.

All models DO NOT have the same harness. There are slight differences (and part numbers) between the euro and non-euro harnesses, and also from year to year and model to model. Also, some ignition switches had up to 5 positions (off + 4). Pic below is from my original owner manual but my bike came with a 3 position (off + 2 positions) switch. go figure...

I haven't done one in a long while, I do however know for a fact, after (illegally ) converting many customer bikes to euro left handlebar switches, that quite a few wires in the multi-plug connector blocks had to be switched around by pressing out the pins and appropriately relocating them. You had to use a multimeter to test and determine which wires went where for everything to function correctly. No wires had to be eliminated or added but in the end the switch plug wire colours would no longer match the harness plug wire colours. I think it was about a 2.5 hour job. These mods varied from bike to bike depending on the year and model. Not a job for the faint of heart, especially if when something effs up decades later.

Red tape: I recall at the time that due to legal and liability concerns BMW Canada was reluctant to import and sell its dealers the euro switches. We (the dealership) told them that they would only be used on Euro-bikes visiting Canada. Dozens of 'em. Ya, right.
Some dealers went so far as to insist that the customer sign a waiver that the bike could no longer be used on public roads just to cover their ass if the customer got a ticket or had an accident. This mod would also void the warranty on any related issues.

[Mallo81]

..so I rewired the bike for 'always-on' headlight. All the wires I needed were already there in the harness. I reasonably expect this was still the case on your RT, as this would keep BMW from having to make different main harnesses for different markets. So if you were to get a Euro switch, it's probably plug-n-play.

All models DO NOT have the same harness. There are slight differences (and part numbers) between the euro and non-euro harnesses, and also from year to year and model to model. Also, some ignition switches had up to 5 positions (off + 4). Pic below is from my original owner manual but my bike came with a 3 position (off + 2 positions) switch. go figure...

I haven't done one in a long while, I do however know for a fact, after (illegally ) converting many customer bikes to euro left handlebar switches, that quite a few wires in the multi-plug connector blocks had to be switched around by pressing out the pins and appropriately relocating them. You had to use a multimeter to test and determine which wires went where for everything to function correctly. No wires had to be eliminated or added but in the end the switch plug wire colours would no longer match the harness plug wire colours. I think it was about a 2.5 hour job. These mods varied from bike to bike depending on the year and model. Not a job for the faint of heart, especially if when something effs up decades later.

Red tape: I recall at the time that due to legal and liability concerns BMW Canada was reluctant to import and sell its dealers the euro switches. We (the dealership) told them that they would only be used on Euro-bikes visiting Canada. Dozens of 'em. Ya, right.
Some dealers went so far as to insist that the customer sign a waiver that the bike could no longer be used on public roads just to cover their ass if the customer got a ticket or had an accident. This mod would also void the warranty on any related issues.

Wow

Awesome explanation, thanks a lot, GSPD

[melville]

OK, I was extrapolating from my 1970s Airheads where it looked like they covered several markets with one harness.

[jagarra]

Mel,

I have bought these from this vendor for all my BMWs, been happy with them. https://www.ebay.com/itm/222432425692?h ... Sw5cNYKjC4