Diode Selection

[Ducati916SPS]

Hello everyone, I'm a retired mechanical engineer which make me even more stupid, I need help with selecting a diode which I hope will solve my problem. I’m looking for advice on selecting a diode for my turn signal for my motorcycle dash conversion. The turn signal dash light wiring does not use a typical ground, the circuit uses the opposite turn signal circuit power wire as ground. I know this might seem confusing it was to me until I found a YOUTUE video on the subject. As I understand it, the dash light bulb draws so little current it doesn't "luminate" the actual opposite turn signal itself. My digital dash has the same visual indicator as on my old analogue dash a double arrow pointing in opposite direction similar to a hazard light, in fact I think it is intended to be used in that manor. So, here's my question, my digital dash must use it's own internal ground and I have two wires from my switch which I plan to tie together however it will light all my turn signals if I simply connect the wires so I think a diode in each switch wire before the connection will work for me however I have no idea what type and size I should install, can someone help me.

 

[rjenkinsgb]

A common 1N4000 series diode (eg. 1N4002 - 1N4007) from each indicator should be fine.
They are rated one amp, the dash light should take only a fraction of that.

Connect the cathodes (banded end) together to feed the dash light (assuming the system is negative ground, as normal).

 

[Diver300]

If your digital dash has two turns signal wires, you can just connect one to each side and you should get one lighting for each side. The digital dash will will have it's own ground.

JRW has described the circuit correctly if you want both lights illuminated for either indicator.

 

[Ducati916SPS]

A common 1N4000 series diode (eg. 1N4002 - 1N4007) from each indicator should be fine.
They are rated one amp, the dash light should take only a fraction of that.

Connect the cathodes (banded end) together to feed the dash light (assuming the system is negative ground, as normal).

Thank you, I'll try the 1N400X and connect as suggested.

 

[Ducati916SPS]

Thank you, I'll try the 1N400X and connect as suggested.

would a 1N4148 work, I have some of these left over from another project?

 

[rjenkinsgb]

A 1N4148 has a rather lower current rating; it should be OK with an LED pilot lamp, but a filament lamp would be too much for it.

 

[Ducati916SPS]

A 1N4148 has a rather lower current rating; it should be OK with an LED pilot lamp, but a filament lamp would be too much for it.

Thank you, it is an LED I believe, the dash is a TFT display so I assume it is LED. I'll purchase an 1N4002 to have margin, thank again.