I have a 1997 Bonneville SSEi. It it November 17th and my heater has stopped working...bad timing. The system does blow air but it is not hot. When I push the temperature control for a higher temperature the blower does increase flow, but it is not hot.

I also had a problem with the air conditioning in the summer. The cold air would blow out of the floor or the defroster but not the middle vents.

I have noticed a whining noise on the AC compressor and suspect this needs replacing. Will this part also impact heat? Please help. I can't imagine no heat in the winter. Thank you very much.

Hi!
The A/C compressor won't cause the heat to stop working, especially if it'* going south. I suspect based on the other A/C problems your problem lies in the internal ducts and doors. I believe they're moved by electric motors, so double-check the various fuse panels. If nothing obvious there, a dashboard teardown may be needed to get to the motors and doors; but I'll defer to another with more experience in your particular model.

Oh, almost forgot. Two other areas that might be of interest. One: Heater Core. Two: Heater Control valve, which turns on and off the hot water to the heater core. More than likely it'* #2 or the vacuum hose that controls it. I'm guessing that piece is up around the passenger side of the firewall in the engine compartment, but you'll have to follow the heater hoses to find it. Try that before pulling your dash apart!

Check the air mix actuator arm. It'* on the passenger side under the dash near the center of the car. I'm guessing it'* not moving so the hot air never gets threw. And I seem to remember that'* vacuum controlled. That module is behind the golve box.

Are these SSEis dual control or single?

There is an electrical air mix actuator on top of the heater box. If you can move the lever arm with a gentle force, the gears inside may have cracked. I took mine on the 98 out and used super glue to fasten the gear to the grey plastic axle which holds the pivot arm. So far it has held.

Here are pictures from the internet that might help.

Yep, what you have there is likely the problem.

Thank you for the replies. I removed the screws to get behind the glove box and it doesn't look like I can do much from there. See the attached picture "Glovebox Removed"

However, under the glove box there appears to be all of the key components. See the attached picture "Under Glovebox". The heater core does not appear to be the problem. I touched the piece under the green and orange wires and it was very hot to the touch. I suspect a valve is not opening / closing at it should. From looking at the picture, which piece controls these valves which is what I suspect needs to be changed.

Thank you so much for your help!

I cycled the mode switch on the ECC and I could hear the unit that receives all of the hoses make a small noise but the system didn't do anything.

This SSEi is single controlled. How do I get to the air mix actuator on top of the heater box?

OK... I think I need to do a dashdoard teardown to get to the electrical air mix actuator on top of the heater box. Is there instructions here on how to do this? Also, there is an airbag on the passenger side dash. Does this significantly complicat things?

Thanks so much for the replies. You guys are great!