My husband's truck was stolen and totalled by someone he knows, so he dropped the theft cahrges because the guy agreed to pay him back a little at a time for the damage. Yet now he refuses to pay anything or sign anything saying he will pay. So is there a way to still press the charges or do anything to get action

Theft is a criminal issue. Its up to a prosecutor to prosecute theft. If you "dropped" the charges once, a prosecutor may not want to take it up again.

What you should do is sue the guy for the cost of the truck and get a judgment against him, then enforce that judgment.

Agreed, the person would merely use the fact you "dropped" charges to show he is not guilty.
You need to sue for the money.

Trying. Thanks