ERRATIC ECC MODE CHANGE INSPECT VACUUM HOSE
SUBJECT: ERRATIC ECC MODE CHANGE OR CRUISE CONTROL UNABLE TO MAINTAIN SET SPEED ON HILLS (ENSURE HOSE CONNECTIONS)
MODELS AFFECTED: 1991 RIVIERA MODELS
Some 1991 Riviera models may exhibit erratic Electronic Climate Control (ECC) mode changes or cruise control that will not maintain a set speed on hills. These conditions may be due to a disconnected vacuum hose. The hose which connects to the vacuum reserve tank, in the right front wheel well area, may become disconnected from snow or ice build up or during an underbody car wash.
To repair this condition ensure that the vacuum hose is seated a minimum of 15 mm (approx. 9/16 in.) onto the vacuum reserve tank connecting nipple.
1. Measure 15 mm (approx. 9/16 in.) from the end of the hose and mark a reference line with tape or white paint.
2. Push the hose onto the nipple until the reference line is flush with the edge of the nipple protector. Refer to Figure 1 and Figure 1, view A.
3. Ensure the proper seat with a moderate tug downward on the hose. If properly seated, the hose should remain secure.
The vacuum reserve tank location shown in the 1991 Riviera Service Manual on page 1B-31, Figure 30 is incorrect. For the correct location, refer to Figure 2 in this bulletin.
WARRANTY INFORMATION:
Labor Operation No.: T6546 Labor Time: 0.2 hour Trouble Code: 92
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.
