I would have had you take voltage readings at the 2 term strips on the side of the card, which takes a few steps since what we would be looking for is the correct inputs to the card at the correct times, and I would have offered a quick way to bench test the SCRs to be sure they turn on and off correctly.
It may well be the card, and at least this way, the card should be eliminated as a problem.
Be sure to come on back and let us know what symptoms you have with the new card, it will likely need to be setup for this truck.
We can 'walk you through it', if you have the time to wait for a reply.