Asking for a 15k loan/loc

I recently got a better job offer than the one I'm currently in. The only caveat is that it requires me to have a personal vehicule ; a 4x4 equipped to handle forestry service road, I work in forestry consultant side). I take home about 3500$/month, but have a credit score of 600 due to a student loc that I accumulated that I used for trade school (certifications/gear). I'm paying it off my interest+minimum amount monthly though. Have a cc fully paid.

I was thinking of taking a 15k loc to pay off my truck, have a budget of 10-15 000$ for it. I dont own a company so can't write it off as a tax writeoff and i'm getting compensated for mileage + any maintenace while working. It would only be a cash advance really that I will pay off during the next few months. What are my chances of getting accepted for this amount? Where should I shop for a low credit score? My personal bank? Any advice? Thanks.