GM Service Manual Online
For 1990-2009 cars only

DFI THIRD GEAR SWITCH TEST INFORMATION

GR.8 DFI THIRD GEAR SWITCH TEST ON PAGE 8D-122 OF THE SERVICE MANUAL, THE FIRST PARAGRAPH SUGGESTS USING A TEST LIGHT TO INDICATE WHETHER CIRCUIT #487 IS AT 5 VOLTS OR GROUND. THIS CIRCUIT SHOULD INSTEAD BE TESTED WITH A VOLTMETER SINCE THE AVAILABLE CURRENT MAY NOT BE ADEQUATE TO ILLUMINATE THE TEST LIGHT

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.