Question about 2005 Buick LaCrosse

1 Answer

Where is the heater control valve on a 2005 Buick Lacrosse?

Posted by on


1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.


    An expert who has answered 1,000 questions.

  • Master
  • 1,547 Answers

It sounds like the heater control valve may be stuck. This valve allows heated water from the engine to pass through the heater core which in turn heats the inside of your car. If this valve is stuck, only a small portion of heated water will pass through. If this is the case, you should have the control valve replace.

You should be able to find it by following the heater hoses coming from the radiator leading back to the firewall. These hoses will about 1/2 - 3/4 of an inch in diameter so you shouldn't get them confused with the normal radiator hoses.

You can probably purchase a new valve at an auto parts store but I'm sure the dealer will have one.

If that's not the problem, it could be that the core itself is clogged up. That's a little more expensive and more of a pain to replace. if this is helpful please dont forget to give rateing thank you

Posted on Dec 29, 2010

  • 2 more comments 
  • Lacros1 Dec 29, 2010

    Yes; the hoses go to the firewall, but there is no heater control valve visible from the engine side of the firewall. So ... assuming that he heater control valvet is somewhere in the passenger area, where exactly is it? Is there a panel of some sort that can be removed to reveal it?

  • Darryl Kazemba
    Darryl Kazemba Jan 26, 2011

    There is NOT any heater control valve in this system, temperature is controlled by use of a actuator that controls the temperature door. The actuator might be inoperative.

  • Lacros1 Feb 24, 2011

    Thanks. As you might guess, my system is not turning out enough heat. The electronic panel on the dash does cause air to move to right places. It just isn't very warm. The thermostat has been replaced, which did not help. I had a dealer check it out, but they could not find a problem. One thing they reported was that heater hose to the heater core is hotter than the hose leaving it (good), which suggests that heat IS being removed through the core.

  • Lacros1 Feb 26, 2011

    Still afflicted with low heat, I made another trip to the dealer and, this time, must have gotten a more knowledgeable mechanic. He thought the circumstance of the hot-hose into the heater core with the cooler hose coming out might have a simpler explanation: The heater core might be clogged. So he back flushed the heater core. The result is that I have heat again. That was an $87 fix that was way better than the other potential work such as (1) replacing the heater core (very labor-intensive), (2) replacing the electronic panel on the dash (I’ve done that with a LeSabre. Be prepared for a huge expense if you let the dealer put in a new one. For that car, once I got a dealer diagnosis that the panel was bad, I bought a panel from a salvage yard at a cost 35 times cheaper than a new one. It worked fine. The downside, of course, was that I was taking a chance on the quality of the one I bought; I had to do the installation; and I still had to pay the dealer for the diagnosis. But it was still way less expensive than having it done at the dealer), (3) replacing the radiator (which, if clogged, can result in too little hot fluid reaching the heater core), or (4) replacing some of the actuators on the side of the heater “box” (it would be labor-intensive to get to them).

    The dealer confirmed, incidentally, that newer Buicks (like this one) no longer use “heater control valves.” They use actuators to open and close doors in the heater “box.” So asking the dealer about a heater control valve on a 2005 LaCrosse may just get you a look of puzzlement.
    Anyway, for the moment at least, I have heat again.
    Thanks for the help



3 Suggested Answers

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this issue over the phone in a minute or two.

Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017

  • 58 Answers

SOURCE: 2005 buick lacrosse heater fan does't run. checked

Check the main fuses under the hood. and check the hook ups under the dash.

Posted on Feb 01, 2010

  • 3911 Answers

SOURCE: How do you change out a heater hose elbow in a

cool car down and drain the radiator, usually a spigot or valve at the bottom. remove the clips or clamps holding the hose on, pull hose off. get a new hose from any parts store, sometime helps to have the old one with you. install new one, put on new clamps and tighten firmly, pour in new coolant. check your owners manual to see what kind of coolant Buick recommends.

Posted on Oct 04, 2010

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Where is the canister purge valve located on a 2005 Buick LaCrosse CXS with a 3.6 L

Remove the plastic cover off top of engine . purge valve solenoid under it.

Evaporative Emission (EVAP) Canister Purge Solenoid Valve
Top rear of the engine, on the intake manifold, near the fuel injectors. If you don't know what it looks like google part to see a picture .

Dec 31, 2016 | 2005 Buick LaCrosse

1 Answer

How to change a heater core in a 2005 Buick Lacrosse

You should not have to pull the whole dash. Take the plenum apart, loosen the hose clamps, remove the core.

Dec 16, 2014 | 2005 Buick LaCrosse

1 Answer


How difficult is it to access the control valve? I didn't find it under the hood so I am assuming it will be under the dash. The fan is working good, and the car is coming up to temperature beautiful.

Nov 28, 2013 | 2006 Buick LaCrosse

1 Answer

Engine diagram for 2005 buick lacrosse

my heater does not work . it only blows cold air please help me

Apr 16, 2012 | 2005 Buick LaCrosse

1 Answer

2005 buick lacrosse heater fan does't run. checked fuses ,all ok.

Check the main fuses under the hood. and check the hook ups under the dash.

Feb 01, 2010 | 2005 Buick LaCrosse

Not finding what you are looking for?
2005 Buick LaCrosse Logo

2,256 people viewed this question

Ask a Question

Usually answered in minutes!

Top Buick Experts


Level 3 Expert

80417 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22326 Answers

Ronny Bennett Sr.
Ronny Bennett Sr.

Level 3 Expert

6927 Answers

Are you a Buick Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides