Getting cash back on a loan is possible but depends on many factors. If you missed a few payments on your house, and it shows on your credit report, then chances are your score is low and getting a loan might be more difficult or you may be approved for a small amount only. If your credit is horrible then forget about a car loan altogether, let alone any cash back.
Cash back would depend on the price of the vehicle and amount financed. Say you get a $40k truck that has $5k of rebates on it. You can tke the $5k off the price and finance only $35k or you can finance the $40k and take $5k cash with you.
On a less expensive car and with bad credit you might be able to get $1000 or maybe only $500 cash back if anything at all.
I would not recommend this because your payments end up being higher and you end up financing that cash back over the term of the loan. It's not free money, and you should in fact care about your interest rate.
If you're short on cash, and you ran into this siutation before, maybe you should rethink buying a new car, and find alternative means of getting around, or buying something reliable but used without needing to finance. And then rethink your financial habits so that you won't need ot finance a car just to get some much needed cash.