Forum

[MikeC]

I have no brake light or near side indicators working on my 350T (the Watsonian model) 2008. I've changed the rear bulb, the brake light switch, and replaced the flasher unit and bulbs with the 23W upgrade supplied by our hosts but the problem persists. I've checked the fuses that I have so far found (one in each toolbox) and they seem OK (I tried switching them with the spare that is stored alongside them in their small hinged plastic box). Perhaps there is another fuse I haven't found?

Any thoughts or wisdom gratefully received. MOT due on Friday!!

[Leon Novello]

If you have power to the live wire, the one that lights a test pencil or moves a meter to 12 volts, then it is probably a bad Chassis Ground (Earth) connection. Look for a loose or broken wire, or rusted connection on that side of the circuit. Start tugging gently at the wire`s terminals to feel if any are loose. You might get a surprise when one comes away in your hand.

[jefrs]

You may have one or more faults. This may appear contradictory - I suggest the fault may be something common to both brake light and indicators. Both the indicators and the brake light use relays, the brake because it has two inputs (front and rear), the indicators because they flash. The relays are usually mounted together in the box. I suggest it may be near there, probably a common grounding point. You need to test continuity of the wires from there. Best tool is probably the ohmmeter on a digital multi-meter, measure the resistance. Don't assume a spare fuse is good, test it with the meter. Check the brake lamp relay. The flasher relay just flashes the indicators, it is the indicator switch that sets left or right, test the switch and the wires from it; both bulbs (left) failing is trying to tell me it is not the lamp units but a fault common to both of them, it could well be at the switch.

[Gwilly]

i would carefully check the harness for damage where it runs around the inside of the rear mudguard and where it leaves the front end and goes upward towards the brake switch..

There is also a plug used as part of the sub assy to the main harness, may just be detached or corroded..

Used to have problems where the harness was too tight and the mudguard would cut through a few wires.

Over sized rear tyre may also chew through cable...

[MikeC]

Thank you for all this wisdom. I'll get to work this evening and keep you posted. Mike

[PeteF]

I'm fairly sure a 2008 model won't have a relay for the brake light. Mine certainly doesn't. The newer EFI models might.

[jefrs]

I was unsure when the brake relay was introduced, certainly by 2010 diagram I've seen. I assume the front brake puts the lamp on? If no relay then the (two?) switches each ground the connection, one lamp, two switches - from supply to lamp to switch(2). For both not to function the fault has to be common both, before the split for the switches.