HVAC Display - Errors or Blower Operation Concerns

File In Section: 1 - HVAC
Bulletin No. 43-11-09A
Date: December, 1994

Subject:
HVAC Display Errors; Left to Right Temperature Differences; and/or Blower Operation Concerns (Replace HVAC Programmer)

Models:
1995 Buick Riviera
1995 Oldsmobile Aurora

VIN Breakpoints:
Buick S4700000 - S4712646
Oldsmobile S4100000 - S4113711

This bulletin is being revised for a word correction in Step # 5. The word "relay" in the previous bulletin has now been changed to "delay". Please discard bulletin 43-11-09 (Group Reference 1 - HVAC).

CONDITION
Some owners may comment on one or more of the following conditions:

1. Outside Air Temperature (OAT) display is not correct on key-up.

2. Auto blower will not turn on when coolant temperature does not exceed 108°F (42°C). This condition is only possible if the coolant temperature that the HVAC system receives over UART (i.e. ckt 800) never exceeds 108°F (42°C) and the coolant sensor is not failed.

3. Large left to right temperature spread in the following position(s): Auto Heat (Buick)/Auto Upper, and Heat (Oldsmobile). This condition may be confirmed by verifying that the passenger zone is off, then using a TECH I, observe PASS OFFSET. It should show a value that corresponds to the owner's concern.

4. Buick HVAC Control Head may intermittently display three dashes, "---". This concern may be more likely to occur if the radio and/or HVAC control settings are being adjusted.

5. Blower remains off if keying up the vehicle in AUTO (Buick)/AUTO FAN (Oldsmobile) modes after selecting manual mode (Bilevel or Defog - Buick)/(Upper, Bilevel, or Defog - Oldsmobile) during delay for coolant temperature. Attempting to select manual mode while the blower motor is off will keep the blower off. The only way to operate the blower motor is by selecting OFF, then any other mode, or by manually adjusting the fan speed.

6. Oldsmobile Passenger Control Head does not always control to the control head setting with pass temp enabled.

CORRECTION
A new HVAC Programmer has been released to correct these conditions (Buick - P/N 16213006 and Oldsmobile - P/N 16213005).

Parts Information
Parts are currently available from GMSPO.

Warranty Information
For vehicles repaired under warranty, use:

Labor Operation Labor Time
D0780 0.5 hr
(Other Hours) Add: 0.3 hr (For diagnosis)