GM Buick/Oldsmobile/Pontiac/Full-Size 1975-1990 Repair Guide

Control Panel



  1. Disconnect the negative battery cable.
  3. Remove the center instrument panel trim. On some models, screws for this panel are covered by the left and right panel trims. If screws are hidden, first remove those panels on either side of the center panel; then remove the center panel.
  5. Slide all controls all the way to the left.

Mark the routing of each cable to each damper lever. Then, unscrew the cable clip attaching screws from the heater case until the cable housing can be freed and the cable can be unhooked from the damper lever; then, free the cable and unhook the damper.

  1. Remove the screws from the control face. Then, pull the face outward until you can gain access to the electrical and/or vacuum connectors. Disconnect all electrical and vacuum connections. Remove the control head, pulling the cables out through the hole in the dash.

To install:
  1. Feed the cables through the hole in the dash and locate the head so the vacuum and electrical connections can be made. Connect vacuum and/or electrical connectors.
  3. Install the mounting screws for the head. Then, connect the cables. Adjust each so that its damper is forced all the way closed or open, depending on its position.
  5. Install the trim panels and moldings in reverse order of their removal.


See Figure 1

To adjust the vent cable, adjust the turnbuckle at the heater end of the cable so the shut-off valve is firmly seated with the selector lever in the heater position. This adjusts the shut-off valve for both the heater and vent modes. The center, left and right vent valve cables are not adjustable.

To adjust the defrost or temperature cables:

  1. Slide the clip at the heater end of the cable away from the end of the cable.
  3. Move the levers at the control to full "HOT" or "DEFROST" position. This adjusts the cables for proper operation of the valves.

To adjust the temperature cable on Tempmatic systems:

  1. Remove the glove compartment.
  3. Align the holes in the programmer lever and the programmer chassis with an awl or a nail.
  5. Check the control panel temperature lever, it should be at 75°.
  7. If not, adjust the turn buckle until the lever indicates 75°.
  9. Remove the awl or nail and install the glove compartment.

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Fig. Fig. 1: Temperature cable adjustment; Tempmatic systems