How large is the battery? Is it the largest group size available for your truck?
Generator output? What amp rating do you have now? What amp ratings are there available as options for your truck?
What condition are your battery cables?
What gauge wire was used to carry the power for the insert?
How long are those power cables?
Combination length and gauge can cause excessive amperage draw causing relays and breakers to trip.
Company that did install uses light gauge wires to save money?
All these things can cause a system wide voltage drop when the insert is used causing relays to trip and trouble codes to be set.