沾光 (zhānguāng) means 'to benefit from someone else's good fortune or connections.' 沾边 (zhānbiān) means 'to be relevant to; to have something to do with.'
mistakes
Don't confuse 沾 (zhān, to moisten/stain) with 粘 (zhān/nián, to stick/adhere). 沾 is about liquid contact or getting something on a surface; 粘 is about sticking together.