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Washington law on a used car or truck purchases is as shown
Washington State Used Car Sales Laws
In March, 2010, Washington added extra protection for used car buyers. The buyer who knows the laws for used vehicle sales has the edge in getting a good deal.
State law RCW 62A.2-314 favors warranties in writing but verbal warranties made by the dealer can also be included if provable. Even an as is sale has an implied warranty of merchantability. Washington State's attorney general explains that "the dealer promises the used car will be fit for ordinary driving purposes, reasonably safe, without major defects and of the average quality of similar cars available for sale in the same price range."
Here is the attorney generals office they would be happy to help you
Dont let them mess with you the truck should be under warranty if it broke down with in 30 days from the sale
If they dont want to give the 10 g back give the attorney General's office a call they will get the state involved and it wont cost you any thing
Let me know how it goes