Low beam not working.

[suzukijax]

High beam is ok but low beam not. Connector has voltage but nothing seems to be happening. This is on a 07, only just happened as MOT was done when I bought it a month ago

[DJ123]

Daft question, but does the low beam part of the bulb work? Is the filament in tact?

[Bibio]

check the fuse box under the pillion seat. will be marked on inside of the lid which one.

[SV650rules]

High beam is ok but low beam not. Connector has voltage but nothing seems to be happening. This is on a 07, only just happened as MOT was done when I bought it a month ago

Does the connector have 12volts on both high and low pins compared to common connector ? As already suggested try a new bulb as the filament can look intact but they can fracture. Sometimes if you tap the headlight it can cause filament ends to touch and light up briefly.

[suzukijax]

Daddyjob. Yes put bulb in different bike and it worked on low beam. Filament is in tact.
Bibio. Yes swapped high beam fuse to low beam and didn't work.
SV650rules. Lower voltage 11 volts on low beam.

[SV650rules]

Try measuring the voltage with a bulb plugged in, If the 11volts disappears with bulb in then you have either a bad contact in hi -low beam switch or somewhere between switch and bulb.

[suzukijax]

Thank you he will give it a try. Probably Monday as he is working weekend. If he gets round to it I will let you know.

[suzukijax]

Still no joy. Voltage at fuse 11.94v. Voltage at white connector at headlight / sub - loom 11.83v. With bulbs in 0.05v. !!!!!

[Bibio]

i take it this is a naked bike?

if voltage is ok upto the connector then i would presume that its a negative (earth) fault. to check run a separate wire from the negative (earth) wire at the bulb holder to the battery negative terminal. you can also do a visa versa with the battery positive going to the low/high on the bulb holder.

once you have established which circuit is at fault then its just a case of tracing back the loom till you find the problem. most of the time with the SV its furred up terminals in connector blocks.

[suzukijax]

Thanks for the quick reply Bibio!
It is a sport, with twin headlights.
Managed to get the low beam to come on by connecting the earth directly from the battery to the earth pin on headlight white connector, and feeding a wire directly from the battery positive terminal to the low beam pin on the headlight white connector.
They also work using a direct connection to the battery earth as above and taking the positive from the highbeam feed at the fuse box, however the voltage drops from 11.9v to 9.5v.
If i connect directly to the low beam feed at the fusebox the low beams don't work, and the voltage drops to nearly 0 volts.

Edit to add - tried connecting loom up normally, and running an earth from one of the bulbs directly to the battery -ve, still no low beam =0(

[Bibio]

if its the sport then there is a small negative terminal block inside the cowling that can fur up. it has a black plastic cover over the top of it with a small clip on the side. remove the cover and inspect the connectors (there is a metal bridge piece, pry off and clean) on the block and apply acf-50.

also the main loom to sub loom connector inside the cowling terminals are notorious for furring up. again apply acf-50

each of the above requires you to remove the whole headlight cowling to gain access to the connectors. on the final removing of the cowling you have to hold the cowling in one hand and undo the main loom to sub loom block at the same time or the cowling wont come off. no need to remove the screen.

when putting the cowling back on remember to connect the main terminal been there done that :-)

[SV650rules]

Sounds like corrosion on the low beam fuse connections, if you get voltage drop down to 9.5v on high beam fuse maybe slight corrosion there as well, or on connector between fuse box and battery.

[suzukijax]

Bibio- He is quite an expert at taking the headlight off now as he has had it off about 10 times in the 2 weeks of me having the bike lol. He has had a look at the negative terminal block, removed the metal bridge piece, cleaned it up, sprayed with ACF50, reassembled but still no low beam.
SV650rules- The battery is measuring 12.1v and high and low pins on the white connector by the clocks both measure about 11.9v. It is only when connected to the headlight assembly that the voltage on the high beam drops to 9.5v and the low beam voltage drops to 0.05v.
The side lights and high beam are still working fine

[suzukijax]

He has just measured the voltage at the black three pin connector that pushes onto the bulb and there is about 11.8v at both high beam and low beam terminals. This is while it is NOT connected to the bulb. With the connector pushed onto the bulb high beam works and measures 10.1v at that terminal. Low beam does not work and measures 0.04v.

[Bibio]

have you tried new bulbs?

have you tried the voltage across the battery terminals while the bike is revving at around 5k?

[suzukijax]

Yes bulbs were the first thing he tried. And yes he has tried revving the bike and testing the voltage he said it was 14v

[suzukijax]

He has just connected the white wire from the main loom to the headlight assembly and we are getting + 11.8v at 3 other pins in the white connector on the headlight assembly - the brown (side lights positive ), the earth pin and the yellow pin (main beam ).
So it looks like the white wire must be shorting out somewhere in the headlight sub loom ... ?

[SV650rules]

When there is no current being drawn ( no bulb in socket ) the voltage on bulb will be same as battery voltage even if connectors are corroded, it is only when current is drawn ( bulb plugged in) you get voltage drop, and the golden rule of electricity is that the largest volt drop is across the largest value of resistance, now the bulb filament is low resistance compared to a corroded connector so you get half a volt across bulb and 11.5 volts across the bad joint. OP said when he connects bulb common direct to battery negative still no joy, but when he bypasses fuse with a wire direct to battery positive the bulb lights up (even when using original earth path), so problem is not in earth circuit, it must be in live feed via the fuse.

[suzukijax]

Just tried another lot of bulbs out of his daytonna and still the same problem but he put my bulbs into his bike and they worked fine. Stripped insulation off headlight sub loom and no obvious damage to white wire where it could be shorting against other wires.
Measuring continuity between the white low beam wire, the brown side light wire, the main black and white earth, and the yellow main beam wire. If we unplug the connectors from the bulbs there is no continuity.

[suzukijax]

Thankyou SV650rules he will check that tomorrow he has had enough now and is off to the pub lol

[NTECUK]

Print out the wiring diagram.
Highlight the current flow on it .
Check the voltages at accessible point and record the voltages with everything plugged in.
Uses a scanner or cam scan app on your phone and post it up.

[NTECUK]

Something like this
http://rs173.pbsrc.com/albums/w63/Martine_V_Brown/IMG_20170822_224710_zpszzwpz7oe.jpg?w=480&h=480&fit=clip

[suzukijax]

Well NTECUK, I ( Chris, Jax's tame bike tinkerer) did as you suggested and managed to find the problem. As usual it was the last terminal i got to =0/

The problem was a bad connection where the left switchgear plugs into the loom. What an absolute PItA that was to access! Tank off, airbox off, throttle bodies off, unhook radiator?!? REALLY? and remove the plastic trim above/behind the rad. There may have been some 'colourful' language around this time....
It still took a while to actually move the connectors where i could get enough purchase on them to disconnect them (both switchgear blocks and the ignition connector block are mounted on the same plate, and the wires wrapped around the cross tube so even when you have managed to unbolt the plate it is impossible to pull them very far up, or down)

...there may have been some more colourful language at this time also.

Once the connectors were unplugged i unwound the wires and that gave me enough slack to be able to test the left switchgear multipin connector. As i was moving the block trying to get the multimeter on it the lights started winking at me! Eureka!!!! Cleaning the pins with a terminal file and spraying them with ACF-50 made little difference so i ended up cutting the white low beam wire and crimping a new pair of spade terminals on.

Success! Thank you all for taking the time to post on this thread, i was rather lost and appreciate the help given, SV650rules explanation of 'the golden rule of electricity' re; resistance and current draw was a massive help. Electricity is all smoke and mirrors to me :smt119

right, the bike's back together, time for :drink:

[NTECUK]

Congratulations .
You all deserve a good drink!

[SV650rules]

Electricity is all smoke and mirrors to me :smt119


Forget all that stuff about electron flow, electricity is only smoke in small copper pipes, have you ever noticed once you see the smoke leak out of any electrical circuit the whole thing stops working.

Glad you fixed it OK

[Ade2005]

Having read loads of the low beam headlights not working, with fuse & bulbs ok on my 2005 SV650S does anyone have pics of where a relay could be causing problems (cant see having removed airbox as i was told but taking fairing off waiting electrician to check few in there?

[Bibio]

as far as i'm aware there is no relay. the culprate is usually a furred up multi plug inside the nosecone under the instrument cluster.

[Sir Trev]

Wow, a six year old thread being resurrected!

Welcome Ade, by the way. Hope you get your issue fixed.

[Ade2005]

Wow, a six year old thread being resurrected!

Welcome Ade, by the way. Hope you get your issue fixed.

Thanks guys really appreciate as suspected will review and get back

[SV650rules]

Corrosion is the enemy on motorbike connectors, it pays to strip and clean any connectors and dose with ACF-50 which is magic stuff..... as it does not damage plastic and actually seems to clean up metal.