1998 Other Oldsmobile Models Panal control doesn't work air

Tom you have either a bad servo on the diverter door, or a vacuum leak in the black vacuum line that comes thru the firewall, this line also goes to a check valve and vacuum resevoir, check all!

How do I replace a servo

Youll need to have a look under the dash, on the plenum, the doors are pened and closed by either a vacuum operated servo, or an electronic actuator, look to see if they have a hose or a plug, either way, there will be screws holding the part on...remove the screws. First operate the controls, while watching to see if the door actuators/servo is working or not. I would look for vacuum leaks first!

can it be done without removing the dash? I won't boyher you any more Thanks.

Tom do yourself A MAJOR FAVOR, YOU ARE LIKE MY SON, HE DOSENT LISTEN EITHER, CHECK FOR THE VACUUM LEAK first, THEN IF IT'S NOT THE PROBLEM WE WILL DO SOMETHING ELSE..ok?

There are no vacuum hoses it's electric. I have the dash and lower panal off. There are two small motors on the right side I disconected both and moved the arm manualy that wasn't the answer. Where would I find the servo?

By the way this is a 1998 LSS

Now that I know whatI'm fixing...scan for "B" codes and it will tell you what part to replace! There are Vac operated parts, here's the diagram...

Mode doors are controlled by vacuum actuators(servo) located on the left side of the heater case. Solinoids on the programmer control vacuum supply to the actuators. In my opinion one of the lines leaks, or one of the actuators is no good, use a hand help vacuum tester and test all the actuators...one will fail to hold vacuum!