Devious, I want to take back what I said to you about carsoft. I recently bought Carsoft 8.2 and it SUCKS! (Anyone want to take it off my hands?) It does not read out the codes in the GM5 and tell you if it's a relay problem. It gives some useless description like F1: 1 Control Module Failure and it doesn't even tell you the raw fault code number like PA Soft 1.3.6 does. PA Soft 1.3.6 doesn't give any description, but, at least it gives the raw fault codes. If you send me the fault codes I can tell you if the fault codes point to a problem with the door lock relays or not.
I'm planning on building a GM5 fault code reader, kinda like the Peake reader, but, without the old cheesey two digit 7-segment LED display. I'm putting in an multi-line LCD display which will read out the fault codes and a brief description so no need for a printed manual with fault code look up. It will also have built in help. Parts are ordered, I just need to finish reverse engineering the Diag bus protocol, write some code and design a PCB.