Yamaha YBR125 Dashboard Electrics Repair Question

Hi guys,

When I got my Yamaha YBR125 Custom (second hand) the dashboard was working fine. After a few months the lights, fuel gauge, and rev metre stopped working. Clearly this was an electrical issue so I debugged a bit, found that there are a few screws on the back of the dash which not only hold components but also seem to conduct the electricity to the dashboard parts. The bolts looked pretty rusted which may have caused the dash electrics to stop working. I did my best to clean the bolts up, screwed them back in and voila! everything worked again. A few months later I brought the bike to the repair shop, they tinkered with some things and the dash electrics aren't working again. Cleaning the screws more didn't help. I'd like to try to buy new screws which may solve the problem (how do I find out what screws they are?), but I am also open to ideas on if there is another issue here.

Thanks so much for your help,

Ilya

Hi. You will find the screws on fowlersparts.co.uk

You should check if you have power and ground on the connector going to the dashboard. If you have power and ground on the connector you know for sure the problem is on the dashboard. What year is your bike? A wiring diagram will tell you what wires to check to power and ground.

Thank you for your reply WD-40. The bike is the 2009 model.

I found that most hardware and diy places can have the screws you need.

Usually a fraction of the price you would pay on a parts shop.

Here's a manual for a 2008 Ybr125. Your 2009 model could be different but I can't find a manual for a 2009. The wiring diagram is on the last page. http://www.clubybr.com/archivos/MANUAL_DE_SERVICIO_YBR_125_CUSTOM.pdf

The brown wire is 12V going to the dashboard when the key is on. That brown wire gives 12V to fuel gauge, tachometer, engine warning light, neutral light. If all those components are faulty the problem could be a on that brown wire or the on the 12V side of the dashboard. The black wire is the ground for the fuel gauge, tachometer, instrument light and high beam indicator. If they're all not working it could be a fault on the black wire or the ground side of the dashboard.

Wiring faults are often from bad connections in connector blocks so check the connector block going to the dashboard first. The wiring diagram shows the connector layout, it's on the left of item 25. It's a 6 pin connector. Check for signs of burning or corrosion in that connector especially on the brown and black pins. If the connector looks good you can check for 12V on the brown wire and ground on the black wire using a multimeter or test light.

To check with a multimeter, turn the key on put the red probe of the meter on the brown wire, put the black probe on battery negative. You should see 12V with the key on and OL with the key off. To test the black wire, put the red probe on battery positive and the black probe on the black wire, you should see 12V all the time. If all that is good you know the wiring in the loom of the bike is good and the fault is in the dashboard or the wire harness going to the dashboard.

You're saying the wires connect to the dashboard with rusty screws? Are those wires brown and black? You can test for 12V and ground on the dashboard at those screws in the same way as you did at the connector. If the screws are rusty, water must be getting in somewhere so check for water damage on the circuit board. All connections have to be clean. Rust could be causing bad connections and high resistance or an open. If you take the dash apart stick up some pictures. It would be interesting to see what it looks like.