ktmlew Posted November 15, 2015 Share Posted November 15, 2015 Have a couple of these that the heater controls seem to work only when they want to. One has intermittent temp control. Other, drivers says heater "cuts out" when under hard acceleration. i tried to check for any body codes but none found. Doesn't appear to use BCM for heater? I may just pay the 20 bucks for 3 days access to GM manuals. If it is the temp control door motor, is there any way to get to it w/o removing the whole dash. Quote Link to comment Share on other sites More sharing options...
ktmlew Posted November 15, 2015 Author Share Posted November 15, 2015 Ok. Subscribed to GM Service Info. Seems it was too obvious...still have knobs cracking. #10012: F/CMVSS Noncompliance - Heating, Ventilation and Air Conditioning Control Knob Fracture - (Mar 11, 2010) 25922402 Knob, Htr & A/C Cont Temp (Single Knob) 3-9 (As needed based on vehicle build (rear controls, etc.)) Quote Link to comment Share on other sites More sharing options...
amailloux Posted November 15, 2015 Share Posted November 15, 2015 That vehicle uses vacuum still. Comes in on the rh side under dash right at doghouse and is easily disconnected or disrupted when putting the doghouse back on. Check for vacuum leaks on the one losing under acceleration. I think the vacuum reservoir is under the battery tray of all places and those side terminal batteries like to leak. Quote Link to comment Share on other sites More sharing options...
ktmlew Posted November 16, 2015 Author Share Posted November 16, 2015 According to service manual the temperature IS controlled by a motor. The "mode doors" are vacuum actuated. I won't be surprised if the one with intermittent temp control is just a broken/cracked knob. The van in question might be a 2011? Need to get prod date. I have only had a few minutes to look at this and when controls were moved NOTHING moved at mechanism on side of case. The mode door for air routing apparently does work as air flow will change from floor/vent/defrost. Just no/very little temp change. Quote Link to comment Share on other sites More sharing options...
amailloux Posted November 16, 2015 Share Posted November 16, 2015 Right, and under acceleration, the default mode door position is Defrost. When vacuum systems were still the norm, the main complaint was I lose heat or ac under heavy load which really means the air stops coming out the vents that blow directly on them. You are right on the temp door thing though. I have had a few over a gallon low on coolant with no overheat issues as well. Quote Link to comment Share on other sites More sharing options...
ktmlew Posted November 16, 2015 Author Share Posted November 16, 2015 I'm hoping for a cracked knob. I checked for vac leaks and coolant level. Even tried applying vac to see if I got heat. No change. Was concerned by lack of any movement of monkey motion linkage on side of box. But if knob is slipping then it wouldn't change. Can't believe we still can't build a heater knob that doesn't break? Benn replacing knobs for better than 30 years. Quote Link to comment Share on other sites More sharing options...
ktmlew Posted December 17, 2015 Author Share Posted December 17, 2015 I'm hoping for a cracked knob. I checked for vac leaks and coolant level. Even tried applying vac to see if I got heat. No change. Was concerned by lack of any movement of monkey motion linkage on side of box. But if knob is slipping then it wouldn't change. Can't believe we still can't build a heater knob that doesn't break? Benn replacing knobs for better than 30 years. Don't you hate it when guys quote themselves? It was the motor on the side of the case in the passenger footwell. i noticed that motor wasn't moving before, but find it difficult to do diag when somebody is looking over my shoulder. Three screws and it's out. A bit tougher to get back in as the doors linkage arm drops down due to gravity...I'll snap a picture of another van later. Didn't realize the heater core is there lying basically flat. The motor moves a blend door. Quote Link to comment Share on other sites More sharing options...
ktmlew Posted December 23, 2015 Author Share Posted December 23, 2015 Well shit...it WAS working? Not sure what wen wrong now... https://www.facebook.com/photo.php?fbid=919337234801684&set=pcb.919337278135013&type=3 Quote Link to comment Share on other sites More sharing options...
ktmlew Posted December 23, 2015 Author Share Posted December 23, 2015 But it seems to be catching. Two in two days... https://scontent-iad3-1.xx.fbcdn.net/hphotos-xtf1/v/t34.0-12/12434636_919311591470915_1053179312_n.jpg?oh=42714149de8706d4c97aa929e92fbc2b&oe=567D53FE Quote Link to comment Share on other sites More sharing options...
ktmlew Posted December 23, 2015 Author Share Posted December 23, 2015 https://scontent-iad3-1.xx.fbcdn.net/hphotos-xfa1/v/t34.0-12/12404678_919313194804088_312959509_n.jpg?oh=f874d368e1dafc4eb73053122a56e7de&oe=567DC186 Quote Link to comment Share on other sites More sharing options...
jimmy57 Posted December 23, 2015 Share Posted December 23, 2015 That last one is a HUGE ouch. IS the driver in the hospital still? Quote Link to comment Share on other sites More sharing options...
Fredsvt Posted December 24, 2015 Share Posted December 24, 2015 Those two remind me of the days at the limo company. They came in groups. From multiple crispy full burns from idiots backwards jumping old 5.0 grand marq and tc, letting the cables stay on and burning two cars to the ground at once, to cars jumping jersey barriers and landing on cars in oncoming lanes. The most interesting was the GMQ that came in on the flatbed, "fuel leak and smell". I got in the car, looked in the rearview mirror, saw a green thing in the window. A sign post punched through the rear shelf. The entire post went through the bottom of the fuel tank, trunk floor, shelf and stopped just touching the rear window. Eye witnesses had the car TEN feet airborne and it landed on the post, which caused the inertia switch to trigger, and it died rolling about 300' after landing. Driver wanted to drive it back, but it wouldn't start, even after tow driver reset switch for him. They both realized the fuel smell was from the car. The car suffered no suspension or frame damage, a new tank, pump and patching the holes up, and off it went. Quote Link to comment Share on other sites More sharing options...
ktmlew Posted December 24, 2015 Author Share Posted December 24, 2015 That last one is a HUGE ouch. IS the driver in the hospital still? Wreck occurred while we were in the middle of company Christmas party. Van showed up about an hour after most had left. Driver was supposedly standing up outside the van after accident but then got really dizzy, Was on way to hospital last we heard. I think guy in green van broke a leg? BIg dude. Quote Link to comment Share on other sites More sharing options...
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