1998 LaSabre-Just defrost and floor vents work

[Gary O]

My 1998 LaSabre climate control only blows air to the windshield and floor no matter what button you hit..I heard about the vacum under the battery on the right side near the wheel well..I did find this 6" oval bulb thing with a broken vaccum hose..the connection to this vaccum bulb??is loose with a peice of hose connected to it ..I bought a peice of hose from a gas station and connected both ends still nothing..Also the buttons only light up when selected(amber light) but all act the same..HELP

[imidazol97]

Originally Posted by Gary O

My 1998 LaSabre climate control only blows air to the windshield and floor no matter what button you hit..I heard about the vacum under the battery on the right side near the wheel well..I did find this 6" oval bulb thing with a broken vaccum hose..the connection to this vaccum bulb??is loose with a peice of hose connected to it ..I bought a peice of hose from a gas station and connected both ends still nothing..Also the buttons only light up when selected(amber light) but all act the same..HELP

First, you need to make sure the tube you found is connected to the vacuum tank. Then you need to verify you have vacuum at that tube when the motor is running. If not, back track and look on the top of the motor where a small plastic tube connects into the upper intake manifold.

Then you need to verify that you have vacuum inside the car. Take off the hush panel above the passenger's feet. Take off the glove box lid with about 7 screws along the bottom.

You'll see a programmer box which controls the switching of the vacuum to move vanes inside the heater box. The purple or violet line goes up the right and connects to the black tube from the engine compartment at a clip. Pull that apart and see if the vacuum is coming there when the motor is running!!!

If you've got vacuum there most likely the problem is the clear plastic connector in the corner of the programmer box==it's about the size of a paperback dictionary. BUT if the vanes in the heater don't move when you put it on bilevel or heat, you don't have vacuum coming inside the car or there's a problem with the electronics.

Do not go replacing parts without diagnosing.

The usual failure is that the AC vents on the front of the dash won't work because the blue tube is blocked inside the clear connector by thin black plastic that's part of the connector. Other vanes will move. Good test is to run car and shut off. For about 30 seconds it should hold enough vacuum to hear the vanes more. If you can't hear other vanes move as you switch the control buttons with the key ON and vacuum in the system, you're not getting vacuum to the inside.

I give it 99% your problem is lack of vacuum completely to the inside. The tank may be cracked in front of the wheel. Your connection may not seal with the replacement part. The connection to the motor is on the backside of the black upper intake manifold plastic. It goes into a connector that's on top of the connector for the big black hose that goes to the brake booster diaphragm on the firewall.

[Gary O]

Thanks for the info..I opened the glove box and seen the pink hose..no vaccume I just have to figure out how to take the engine cover off to look at the connections to the intake manifold..It looks like it disconects at the oil cap but I see FUEL LINES attached to the cover on top a little nervous..Gary

[BNaylor]

Twist the oil filler with the cap counterclockwise and remove. Then grab plastic cover up and out to remove. The source of the vacuum line for HVAC accessory vacuum is located at the rear of the upper intake manifold (plenum). At the Y fitting is is also a one way check valve. Same one that feeds the power brake booster.

[imidazol97]

Originally Posted by Gary O

Thanks for the info..I opened the glove box and seen the pink hose..no vaccume I just have to figure out how to take the engine cover off to look at the connections to the intake manifold..It looks like it disconects at the oil cap but I see FUEL LINES attached to the cover on top a little nervous..Gary

Don't forget the storage tank for vacuum under the fender in front of the right wheel! You can pull the black tube off there and test to see if it has vacuum when the car is running. The tank may be cracked or damaged.

[imidazol97]

Originally Posted by Gary O

I did find this 6" oval bulb thing with a broken vaccum hose..the connection to this vaccum bulb??is loose with a peice of hose connected to it ..I bought a peice of hose from a gas station and connected both ends still nothing..Also the buttons only light up when selected(amber light) but all act the same..HELP

This sounds like the storage tank. It may be cracked and leaking even though you connected a new tube to it. Try closing off the end of the tube coming from the engine compartment. Cover it with a plastic bag and put a tight rubber band around it, e.g., to seal it.

Then with the motor running see if you get vacuum inside the car to make the switches move the vacuum motors ont he heater box!

The system can run without that storage tank. All it does is keep vacuum in reserve in case of a long uphill pull where the motor loses vacuum.

Good luck.