Engine has heat, but no heat for jack!

[jackmalone2001]

Hi everybody!

I have a 1999 Buick LeSabre, 3.8l v-6, 170,000 miles and there is no heat, defrost or vent in the car. I have the auto climate control that is supposed to come on at a specific temp, and that sences the correct outdoor temp but the heat is not coming on at all. No fan noice, no air flow, nothing. I went under the hood and there is fluid in the radiator overflow container, the top radiator hose is hot, but the lower radiator hose is quite cool.

Any ideas?

(it was -4 degrees this morning in balmy Cleveland, Ohio...)

Thank you! Jack

[Blue)(Fusion]

Originally Posted by jackmalone2001

(it was -4 degrees this morning in balmy Cleveland, Ohio...)

Being from there myself, I know it's not the heat that will kill you, but the humidity ;-)

When you felt the top and bottom hose temperatures, was the engine up to normal operating temperatures for atleast 10 minutes? If not, then I'm not surprised the bottom hose is cold. If it was that long, then there may be an air pocket in your system preventing proper coolant flow. If you didn't have the coolant changed recently, this is probably unlikely.

Also, when the engine is at normal operating temperature, follow the small coolant lines near the passenger side firewall. Those lead to the heating core and should be hot. If they are not, that also indicates there is a blockage in the system.

You did mention that there was no fan noise when you turned on the heat, either. This sounds like a bad blower motor or a blown fuse. Check your car's manual for the corresponding fuse to the blower motor and see if that looks blown. If not, the next step is to see if the blower motor is working. If you have a multimeter laying around, you can use that to verify there is a current going through the wires to the motor. If that is the case, then the motor has failed thus not providing the driver with any heat.

[jackmalone2001]

That was hilarious!
I checked the hoses after about twenty minutes driving time, so I am sure it was up to temp. What about the car's thermostat? Could it be stuck closed causing no coolant flow through the engine? (hence the cool lower radiator hose...) The car's climate control system doen't turn on until it warms up, therefore, if the temp sensor in the climate control isn't seeing any heat it wont turn on, so I am going to focus on fluid flow through the coil. Thanks for the reply!

[HotZ28]

Originally Posted by Blue)(Fusion

Check your car's manual for the corresponding fuse to the blower motor and see if that looks blown.

The auto climate control system does not use a fuse for the fan control, it feeds direct from battery 12v+ to the blower control module.

Originally Posted by jackmalone2001

The car's climate control system doen't turn on until it warms up, therefore, if the temp sensor in the climate control isn't seeing any heat it wont turn on,

Will the fan run if you bypass auto climate control & put it in the vent mode, or use the fan speed control? If you do not have anyway to monitor engine temp, take it by your local parts store & have them check engine temp with a scanner. This would also be a good time to let them test your coolant to see if it is good for temps @ -4 deg? If not, it could be turning to slush in the radiator and restricting flow!

Originally Posted by jackmalone2001

I have the auto climate control that is supposed to come on at a specific temp, and that sences the correct outdoor temp but the heat is not coming on at all.

The engine temp must reach 120-140 deg before the auto climate control will allow the fan to run in auto mode only. Outside temp has nothing to do with this function, other than how long it takes for the engine to reach that temp. The PCM provides engine temp readings to the auto climate control to enable this function.

[jackmalone2001]

Hi Hotz28,

How are you doing?

The fan will not come on at any setting of the climate control system. I have an infrared thermometer, that I shot at the upper radiator hose, and it came up 130 deg F. so I think the system is circulating fluid.

If the fan is controlled by the BCM, can I just replace it? Is it very expensive?

Or is there anything else I can do?

Thank you again everybody!

Jack

[HotZ28]

Hi Jack, I would first try to determine if the fan motor is getting power from the blower control module. You can remove the terminal from the fan motor and probe it with the leads from a DVM, (if you have one). If you have voltage going to the motor, suspect the motor. Try bumping the motor with a mallet (if you have voltage) it may come on, but if not, you should replace the motor. The motor typically cost 50-100 bucks depending on the brand or if you get the unit with the fan included. Good luck!

[jackmalone2001]

That's great advice Z.

The latest in this saga of no heat in the frozen mid-west is that I took my Bride to work this morning (17 deg F @ 06:45) and turned on the front defroster and it worked! Fan came on, heat, glorious warmth, bathed the interior of my car like I was sitting poolside at some resort in Mexico, watching the bikinis and sipping on one of those fruity cocktails you see in the movies!

But then...

I went home, turned the car off, got ready for work and then when I went to turn the car on, no fan, no warmth, no Mexico, no fruity cocktails, and definately no bikinis.

I think that there may be something stopping the motor from turning (leaves and junk) or the motor is going, or has gone, bad. I will check with my buddy "Chilton" and look into fan motor removal, see what's what and go from there.

Any tips or hints on bench testing a 12v DC motor? Removing said motor, or how I can get that vision of Mexico back in my skull?

Thanks everybody, this site Rocks!

Jack

[imidazol97]

Originally Posted by jackmalone2001

The latest in this saga of no heat in the frozen mid-west is that I took my Bride to work this morning (17 deg F @ 06:45) and turned on the front defroster and it worked! Fan came on, heat, glorious warmth, bathed the interior of my car like I was sitting poolside at some resort in Mexico, watching the bikinis and sipping on one of those fruity cocktails you see in the movies!


I think that there may be something stopping the motor from turning (leaves and junk) or the motor is going, or has gone, bad. I will check with my buddy "Chilton" and look into fan motor removal, see what's what and go from there.

Any tips or hints on bench testing a 12v DC motor? Removing said motor, Jack

It sounds like you've got multiple places for problems.

Blower motor:

As Z28 suggested trying hitting it gently with a rubber mallet or other object to vibrate the motor. When it won't run, leave the key on and tap it. It may be sticking between worn contact points and not getting power until a bump lets it make contact.

You can bench test the motor without removing it. You can use a direct wire with a fuse in it from the battery to the motor lead to see if it will run with battery power. When it's not working, jumper it--you may have to provide a ground wire. If it runs with direct power and doesn't run when plugged back in, you know the motor is capable of running and may not be getting power. Most likely would be the blower control module that Z28 mentioned. The module is on top of the box the blower sits in and is where the blower motor wires lead. It is mostly inside the box for cooling in the air stream. Available at parts stores, rockauto.com, recycling yards, etc.

If the blower has things keeping it from turning, you'd hear noise from bearings or stuff caught in the squirrel cage blades.

The blower has a few screws holding it in place and can be wiggled out.

Thermostat and coolant:

What does the coolant look like? Is it bad looking? DexCool should be a brown-orange. It should not have a sludge or goopy look other than a fine layer of brown sealer that collects on the plastic of the reservoir that was put into the motor which is ground up almond shells or oregano.

Your thermostat housing should be nearly 190 with your infrared temp gun when it's all warmed up. Thermostat may not be closing completely and slowing warmup. It might be time to replace it with a quality replacement if it's original to the car.

Did you check the coolant level in the radiator? Sometimes the level there can drop due to leaks in the system letting in air when the coolant contracts and cools.

Were both heater hoses the same temperature when the blower was running. There should be enough coolant flow through the heater core with the blower taking heat out that the exit hose is almost the same as the input hose.

Good luck. It's cold here in W. Central Ohio.

[big white bufflo]

could be the blower resistor witch is located in the blower duct under the hood follow your wires back to the fire wall and that is were the resistor i have a 92 and it did the same thing one time it would not turn off w/key i pulled the fuse then worked fine the quit working totaly

[jackmalone2001]

I put a new blower motor in and she works like a charm.

The people who resonded saved me hundreds of dollars, and I am really appreciative.

This site rocks!

I posted a question in the Camaro forum about finding a 3.4l V6 rebuilt/new engine newar Cleveland. If you have any ideas please respond!

Thanks again everybody!

Jack

[imidazol97]

Originally Posted by jackmalone2001

I put a new blower motor in and she works like a charm.
The people who resonded saved me hundreds of dollars, and I am really appreciative.
This site rocks!
Jack

How did you decide it was the blower motor? Did the tap test work?
Thanks for posting about your success at fixing it.

[jackmalone2001]

Yes, the tap test worked like a charm, and let me know that it was a localized problem.

Thank you again!

Jack