着きしだい君に連絡するよ。

isn’t 君 pronounced きみ here and not くん?

@pretsplay
君 in this sentence should be pronounced as きみ because it means “you”. くん is used when preceded by a person’s surname, first name, or nickname (e.g. 田中君 = たなかくん, meaning “Mr. Tanaka” (casual)).