IANAL. The law linked by Loach states that a driver has to “stop and submit to inspection”. It seems to me that submitting does not include assisting with the inspection, beyond what’s necessary to allow the officer to perform the inspection himself. So give him the keys to everything, produce the required records, and you’re within the requirements of the law.
But you’ve now annoyed the officer who is going to actually perform the inspection, without in any way limiting his ability to do so. It’s not like the case if an officer asks if you consent to him searching your private vehicle and you say “No”, and he has no further legal power to do so. He’s going to turn those switches on himself anyway, so you’re going to get dinged for the same penalties regardless of whether you assist in the inspection or not.
Plus the inspection will now take longer, and you’re less likely to get away with a warning for any minor infractions.