Warning: I’m not a native English speaker, nor am I a professional translator. I’m pretty sure your French is better than my English, so don’t take my proposed translations at face value.

That French sentence is indeed quite poorly written. In particular, the “à imposant” doesn’t mean anything. Moreover, if one understands it as “imposant” or as “en imposant”, the meanings are completely different.

[…]renoncerait à toute réclamation imposant au fabricant […]

[…]would waive any complaint which would oblige the manufacturer[…]

Basically, if it breaks, that is your problem, not the manufacturer’s. You waive the rights to complain by agreeing to the contract / buying the product.

[…]renoncerait à toute réclamation en imposant au fabricant l’élaboration […]

[…]would waive any complaint by requiring from the manufacturer […]

If it breaks and you require replacement, you waive some rights of complaint. You waive these rights by reclaiming another product, not by agreeing to the terms in the first place.

À imposant is simply not correct French.
En imposant means “by forcing”,
imposant means “which force”.