GMC Troubleshooting Questions? Ask a Mechanic for Answers
Hi my name is ***** ***** be happy to assist with this today.
One common issue I have seen cause a fault like this here is a fault with one of the battery cables being dirty or corroded and in some cases high resistance in one of the battery cables.
If you have not checked to see if any cable is found dirty or corroded causing this fault here or if any appear damaged this needs done.
Make sure the connections at the starter and alternator are clean and tight as well.
If these are or were checked and found to be o.k. Let me know so we can continue.
Let me know if you need anything else and feel free to rate my help here.