I am trying to find out how I can fix the tpm on.

I am trying to find out how I can fix the tpm on my colorado 2.9 liter, I have had the tpm checked and they are fine, the tire pressures are fine, the dealer says the relays need to be cleaned, is there a way that I can do this myself and how many are there and where located? The tpm light still comes on telling me its has low tire pressure