Idiots guide to electrics

[Adam]

I've got a short somewhere on my bike, my horn doesn't work, my speedo has stopped working and my engine warning light keeps coming on. I think they're definitely all related because they've happened one after the other. Now I've had a look at the plugs and sprayed them with wd40 but this hasn't helped so I'm going to get the multi metre out but I'm clueless when it comes to electrics so...

What setting do I need the multimeter on?

Do I test the wires one side of the plug then the other?

What voltages am I looking for roughly?

Any other tips?

Cheers

Edit

Found wiring diagrams if there's anything I should check first could you let me know please

[Chrissb6]

Hi give the loom switches and components a good physical going over first look for any loose dirty connections, kinked, trapped or broken wires especially around the steering head where the cables are pushed and pulled every time you turn the bike. then open up the connectors one by one and look for any form of corrosion if nothing found that's obvious it starts getting serious, and if l'm honest, if you not electrical minded it's probably better to find somebody who is. By the time you have brought a meter and then fried your brain learning how to use it, you might wish you had. But first things first give it a good looking over.

[rennie]

Ok if you're trying to measure voltage you need meter set on DC volts usually 0-30V with a straight line above it.

To measure continuity you need meter set on Ohms, some meters will buzz on this setting if you touch the leads

together. This is useful for confirming a connection between 2 places or confirming that there is no connection

where there shouldn't be.

If in doubt take a pic of the meter and show me

[littlecat]

easiest test is for continuity across all the connectors first... theyre prone to going tits up in my experience.

if all the connectors test ok, then you are looking for a possible short... that's where it starts to get complicated

[Adam]

It's just a standard one Ian like the picture below. The engine warning light flashed a code the other day of 4-2 which is speedo error so the ecu is wondering why the engine is under strain but according to the speedo it's not moving. So that's them sorted but the horn still isn't working so I'm going to investigate when I can if the weather lets me!!!

[Tango]

Switch the rotary switch to 20 in the DCV section....black test lead goes on the COM socket and red test lead in the V ohm,mA socket.

Put the black lead to the bike frame or engine ground connection and then put the red lead to the terminals on the horn....with the ignition on you should have 12v ish on both terminals....then when you push the horn button one of the terminals should go to 0v and the horn should sound. The horn has a 12v supply going to it and the horn button connects the other side to ground, putting 12v across the horn.

Be careful though, coz the horn on my old bike didn't sound unless the engine was running.....so just be wary of that.

[Adam]

Cheers for the info bob, it definitely doesn't work when running I tried that before and ended up replacing the horn but that didn't work either so bodged it for the mot with a feed directly from the battery. I'll find the thread again so you can read what was happening viewtopic.php?f=5&t=52065&start=0 I check plugs and sprayed them with wd40 on Saturday but again that didn't help which is why I'm now going to try it out with the multimeter, let's hope this rain stops..