NO COLD START OR HOT RESTART DIAGNOSIS/PART NUMBER

MODELS: 1983-89 C/K/R/V/G AND P MODELS WITH 6.2L DIESEL ENGINES (VIN CODE C,J)

Some customer comments have been received regarding no cold start capability or hot restart difficulty during mid-range engine temperature. Cases of no cold start may be the result of the glow plug inhibit switch not operating correctly. Reference Corporate Service Bulletin #866001 for glow plug system diagnosis.* Meanwhile, cases of poor hot/warm engine startup may be the result of starting system degradation, and may require glow plug assistance for engine starting. Replacement of the existing glow plug inhibit switch with a new service switch without a coolant temperature sensor (listed below) will provide glow plug assistance upon engine start, regardless of engine coolant temperatures. This feature will not reduce glow plug life.

New Part Numbers

1983-87 LH6*/LL4 - 23504005 1988-89 LL4 (Only) - 23504006 *1988-89 LH6 not equipped with glow plug inhibit switch

Service Switch Without Sensor Installation

1. Disconnect batteries.

2. Replacement service switch can be installed in exact location of the inhibit switch with a socket wrench. (Do not use open end wrench.) Tighten to 19-27 Nm (13-20 lbs/ft). Replace any lost coolant.

3. Connect glow plug inhibit switch connector assembly to service switch.

4. Reconnect batteries.

IMPORTANT: Glow plug operation (Wait Lamp) will be observed more frequently on the hot engine restarts with the installation of this service switch.

Parts are currently available from GMSPO.

* Chevrolet Bulletin #88-49, GMC Truck Bulletin 88-T-39 and GM of Canada #88-662-100

Use applicable labor operation number and time.

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.