For 1990-2009 cars

# DIESEL ROUGH IDLE GLOW PLUG RESISTANCE TEST INFORMATION

HIGH ALTERNATOR OUTPUT MAY AFFECT THE GLOW PLUG READINGS FROM LEFT SIDE TO RIGHT SIDE WHEN THE RESISTANCE TEST IS BEING CONDUCTED. HIGH ALTERNATOR OUTPUT WILL OCCUR ON A LOW CHARGE BATTERY OR WITH ACCESSORIES ON. TO PREVENT THE ALTERNATOR OUTPUT FROM AFFECTING THE RESISTANCE TEST, DISCONNECT THE TWO WIRE CONNECTOR AT THE ALTERNATOR.

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.