Once you have your signal bulb out you can clean the connections and maybe pry the contact in the bulb holder up a little to make sure it’s making good contact. This video shows a lot of other stuff but also how to pry the connector up a little. https://m.youtube.com/watch?v=yxzr28zLrxM If you don’t feel comfortable with this, really any shop should be able to fix a bad ground. Just go somewhere with good reviews. Tell them what the problem is and you should just be looking at an hour of shop time. Shouldn’t need any new parts.