Heat Not Blowing Out

[hansens69]

I have a 1997 Yukon and the heat is now blowing out. I've replaced the heater controls (switch went bad) and replaced the blower motor. I can feel a small amount of heat blowing out of the vents but I can't adjust the amount that blows out (nothing happens). What else could it be?

 

Thanks.

[VMax2007]

Blend door actuator?

[hansens69]

Where is that located?

[bflat]

Have fun with this one, You will be removing alot to reach the blend actuator. My recirc. went out on my truck, after several attempts to fix it, I finally gave it to a quailfied mechanic. That is one area of the truck I hate to work in. You have to be a contortionist!

[Operation Mindcrime]

Have fun with this one, You will be removing alot to reach the blend actuator. My recirc. went out on my truck, after several attempts to fix it, I finally gave it to a quailfied mechanic. That is one area of the truck I hate to work in. You have to be a contortionist!

Blend door could be possible, any work done recently or before this no heat started??

Your model may have a small vacuum switch located on the firewall(engine side).

Look next to the A-C receiver/filter/fryer. That big silver tank located on passenger side next to firewall. Look just below and towards the passenger side valve cover and look for a vacuum switch with 2 hoses connected. Try switching the hoses and see if that helps. I've seen a few DIY's try to reseal their own Intake Manifold and these hoses are among the several things that get screwed up. As fas as the blend door actuator you need to remove part of the lower dash trim to see if the (heat/cold air motor??) is moving full swing before continuing on.

[lbkthree]

Could be a clogged heater core. Sometimes they aren't 100% clogged and flow a little, which gives you little heat.