What is this part?

[SLIMSHADIE]

I am having starting issues. The starter works sometimes and not others. Its like I dont have power. But I do, the nuetral light works and so do the headlights. Battery may be 2 years old.
I replaced the starter only to work twice, then not again till tonite.
I was looking at the ignition coil to make sure there was good connections, thought about replacing.
When I looked at this relay? or fuse? I unplug it, the lights still work. I plug it back in and then accidentally hit my starter button it it starts. I unplug, hit the button-nothing. Plug it back in and it starts!

The markings on it is

100858
---l<--

It has a green and yellow wire,which I believe run to the handlebar switch-H/L/O/START

I was thinking about replacing it but cant find it in the manual or online??
I dont like being stranded out in the middle of nowhere, any thoughts?

[SMP63]

Hello!! You might want to let the guys here know what bike it is.
Model & year i'm sure would be helpfull!!! Looks like some kind of fuse or relay. Sorry i can't be of more help!

[SLIMSHADIE]

Its a 2005 Predator 500 TLD.
I thought since I was in the Pred Forum and my sig and my orange plastics wood give it away, sorry.

[ZSK]

It's a diode. You should have current across it one way but not the other. It's like a check valve in plumbing.

[SLIMSHADIE]

I ordererd a new diode thru the dealer,$12. So far after cleaning the connections, the old one is working every time.