If you have past due HOA fees the HOA may still persure for past due fees even if you no longer own the Condo.
In order for them to garnish your wages they will have to win a judgement against you in civil/small claims court.
Sounds like you are at a point where you can get this cleared up withou having to defend yourself in court.
Try to work out a payment plan with them. If this fails and they file a small claims case against make sure you appear in court and ask for meditaion. If you two meidate the case and reach a payment agreement, as long as you make the scheduled payments your wages will no t be subject to garnishment. If you fail to appear in court they will win a default judgement against you, and can garnish your wages 30 days after the judgement is entered.
If they file a civil csae against you, you will need an attorney to represent you in court.
Best bet, try to work a payment plan out and avoid any legal action.
Best Of Luck to you!