Learn Spanish (Latin America): Les pedimos afinar los instrumentos.

Usually, a change of subject triggers que + subjunctive. However, with verbs of influence (like pedir, permitir, prohibir, mandar), Spanish allows a special shortcut. Because the person doing the tuning is already represented by the indirect object pronoun les, you can just attach the infinitive afinar. You could also say Les pedimos que afinen los instrumentos, which is equally correct!

If we used the subjunctive version (que afinen), where would the pronoun les go?

It stays exactly where it is! The sentence becomes Les pedimos que afinen los instrumentos. The pronoun les belongs to the verb pedimos, because it tells us to whom we are making the request.

Could pedimos also mean 'we asked' in the past tense here?

Yes, the form pedimos is identical in both the present tense ('we ask') and the preterite tense ('we asked'). You would rely on the surrounding context to know when the request happened. Note that if this were in the past tense, the alternative subjunctive version of this sentence would have to shift to the past subjunctive: Les pedimos que afinaran los instrumentos.

Why use pedir instead of preguntar for 'to ask'?