Power locks

My 88 Silverado is equipped with power locks and windows. I bought the truck from my older brother who had installed a remote access and starting system. He told me that the system was bad so he removed it. Before he removed it everything worked perfectly locks and windows. After he pulled it out the locks quit working. I have wiring diagrams and everything and have tried to track down the problem. I have had no luck. Everything is plugged in where it is supposed to be. I wonder if the lock mechanisms are wired in series and one shorted out but the diagram shows that they are in parallel. Any advise would be helpful.

Have you verified that the circuit breaker works? Is it getting power to it? Is there power going to the switches? Were any wires cut for installation and forgot about come removal time?