Used 1999 GMC Sierra 2500 Extended Cab Consumer Reviews
ABS electronic module - replaced by dealer in Virgina only problem. Drove 300 miles to pick up - has one of first 6.0 liter engines. Great power. Engine does not show up as option in parts stores until 2001.
4WD light comes on intermittently lately. Poor troubleshooting procedures from a Chilton manual led me to replace the front diff actuator motor. Seems the real culprit is a sticky selector switch. Humidity may be affecting this switch, apparently the resistors are shot for each position and loses ability to keep voltage signal to transfer case module. Original battery lasted 6 years so that was awesome to get over 6 years from a battery. Also developed a leak at the front differential. First thought it was the output seal but ended up being the plastic vent cap that screws into the diff.