relays

[happy pilgrim]

battery went flat on 1200gs. it would not take a charge using bmw's fancy battery charging thing. so we used jump leads off another 1200 to get it going? when we arrived at the dealers the fog lights would not switch off? even when the keys removed from the bike??? could the battery fault cause the relay to pack up?

 

[BTBR]

battery went flat on 1200gs. it would not take a charge using bmw's fancy battery charging thing. so we used jump leads off another 1200 to get it going? when we arrived at the dealers the fog lights would not switch off? even when the keys removed from the bike??? could the battery fault cause the relay to pack up?

All depends on how the lights are wired in?

If there is a signal wire from the dipped beam headlight, then no. This circuit is only live once the engine is running.

But it sounds to me like the relay has stuck in the closed position, normally caused by exceeding the current rating of the relay.

So when the signal feed is switched off, the relay contacts have been burnt together.

Maybe a spike as a result of jump starting it?

Jump starting anything that has a canbus system is never a good thing to do, for that very reason.

 

[rc mad]

i had a good one earlier in the week, aux lights would not switch on, traced back to the relay contacts not closing. The relay coil energised and the lights worked if the relay was bypassed. Bought a new relay and now the old one now works perfectly

It was definatly toast when i tested it.

 

[Yoda]

I fail to see how using jump leads would spike a relay (or why it should be an issue on canbus). It's just the same as unbolting a shagged battery and bolting in a spakly new one.

It sounds that the relay was knackered in the first instance, had stuck shut, thus leaving the lights on and flattening the battery.

Just my 2c.

 

[BTBR]

I fail to see how using jump leads would spike a relay (or why it should be an issue on canbus). It's just the same as unbolting a shagged battery and bolting in a spakly new one.

I agree, but I am only going by what all of the truck manufactures tell us NOT to do.

Before jump starting trucks you are supposed to disconnect the ECU first, if memory serves me correct.

 

[happy pilgrim]

ok thanks all.

 

[Steptoe]

.

Before jump starting trucks you are supposed to disconnect the ECU first, if memory serves me correct.

Not at all familier with trucks, but any other vehicle won't start with the ECU disconnected

 

[littleredrooster]

I fail to see how using jump leads would spike a relay (or why it should be an issue on canbus). It's just the same as unbolting a shagged battery and bolting in a spakly new one.

It sounds that the relay was knackered in the first instance, had stuck shut, thus leaving the lights on and flattening the battery.

Just my 2c.

MMmm.....not quite. When connecting jump leads, you have a massive resistance in the circuit (the flat battery) which wants to suck the life out of the donor battery. This produces an initial massive current flow into the flat battery, hence all the sparks when you connect.

What this has to do with the price of cheese I'm not sure, but the flashing/sparking can be entertaining.

I concur with everything else in your post, BTW.