GMC Repair: ABS and Brake Light Coming on in 01 Yukon, antilock brake system, brake fluid

Question
The ABS and Brake Light is coming on while driving our GMC 01 Yukon.  This does not happen all of the time.  Our truck has 116000 miles on it and we just had service done on all belts, etc.  The truck runs great.  We have had the brakes checked and have added additional brake fluid.  What is the issue of these lights and what needs to be done to have this corrected?  

Answer
Hi
You'll need to take vehicle to a repair shop that can scan the Antilock Brake system, and retrieve the trouble codes.
They will then need to diagnosis these codes. There are many things that can make these lights come on together, so getting the ABS diagnosis done will be the quickest and easiest.
Thanks and I am sorry I can not be of more help.
Paul