Lights, dip beam circuit offline

[Gusdeadman]

Hi,
So I dropped the r1200gs against the pump at a French filling station and when I'd got it upright after straightening the screen and mirror I found the dip beam wasn't on. The bulb was fine but I changed it anyway which didn't solve the problem. I eventually got the dip working by temporarily using the main beam connection on the dip bulb. The weird thing is that the dash shows the dip beam circuit is disconnected. There are only two wires to the dip bulb, if the bike knows the circuit is disconnected, how can it not be delivering power? Clearly there is an answer, the manual is not helpful, but does anyone know where I would start with diagnosing this issue?

Cheers Andy

 

[TLSgazza]

Did you bash the left handlebar switch on the pump. May have damaged the switch affecting low beam. Apart from that I don't know. Strange one.

 

[Gusdeadman]

Did you bash the left handlebar switch on the pump. May have damaged the switch affecting low beam. Apart from that I don't know. Strange one.

Good point but it went down on the right. There has to be something I think I'll start wiggling wires.

 

[squibb34]

Some say the resolution to many weird BMW electrical problems is often to simply disconnect the battery for 20 minutes plus, making sure it is in good, fully charged condition before reconnecting & , effectively, rebooting the whole system.

You don't say whether the bike was running or not at the time of your spill. However, I'm thinking it's a connector between the ZFE & the headlamp, assuming the connectors at the bulb aren't showing any witness of overheating. As you probably know, the circuits are checked for continuity when you turn the key, but full power to the low beam is isn't applied until after the engine starts. As I understand it, the ZFE will supply power to the lamp even when the bulb has failed. If you are not measuring 12-14 v at the lamp socket check the connector that feeds the headlamp housing. If that connector is OK and you still don't have voltage I'd suspect a wiring problem. The ZFE will cut power to the headlamp circuit if it sees an excessive current draw.

Good luck finding the culprit.

 

[MWH]

Sometimes when your battery is on the way out the dip beam doesn't come on. Mine did this, started OK etc but no dip. New battery and hasn't happened since. Was a while ago, can you hook up a decent battery using small jump leads and see if it comes on with the ignition?

 

[Gusdeadman]

Sometimes when your battery is on the way out the dip beam doesn't come on. Mine did this, started OK etc but no dip. New battery and hasn't happened since. Was a while ago, can you hook up a decent battery using small jump leads and see if it comes on with the ignition?

Thanks I had considered it might be battery related but main beam comes on ok so I think the issue is something else.

Cheers

Andy

 

[Gelandestrasse]

From Mr Haynes circuit diagram there is nothing but cable between the ZFE unit and the dip bean live connector (ie no switches, relays etc but there is possibly an inline connector). The high beam uses the same earth as the dip, so the earth path can be ruled out. I think you have a break in the yellow cable somewhere, like a connector along the cable, the pin (33) pulled in the big connector or a chafed cable that finally got severed when it went down. I can't remember if or where the connector for the dip supply is. But it's worth con-checking it from the big ZFE connector to the headlight.

 

[MWH]

My main beam and auxiliary lights still worked and the bike started. Doesn't hurt to try, that's why I suggested jump leads to a decent battery before forking out for a replacement just in case it isn't that.

 

[Mistacat]

The fact that the dip beam started working after a battery change #5 may make it worth while just disconnecting the battery for five minutes.
The ZFE has a permanent live feed from the battery so this will re boot it and clear any glitches. Jump leads will not have this effect.
Worth a try and cost nothing.