Last post on Jan 29, 2013 at 2:06 PM
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Chevrolet, Heating / Cooling, SUV
#58 of 154 2001 Chevrolet blazer ZR2
Dec 15, 2007 (7:29 pm)
I have been trying to troubleshoot my ZR2's lack of heating. ( see message # 53 ) I have found that after the engine has reached temperature 195 deg. and I have the fan on with the heat on ( NO climate control ) I have about 165 deg. on the inlet hose to my heater core and about 109 deg. on the return line from the core.If I take the truck for a short drive I have heat coming out like I usually did. After driving approx. 5 mins. I start to loose heat out of my air supply ducts. Is this a partially plugged heater core ? I only have 58 k miles on the truck . I also noticed that with the truck ideling, the heater on / fan on 2, my A/C compressor clutch was kicking on / off sparatically. After returning from a short drive to test it, the A/C comp. did not kick in. Any help would be appreciated.
#59 of 154 98 s-10 blazer heater door
Dec 28, 2007 (12:19 pm)
have read all the threads about the blend door & related. This 98 is on its fourth heater door, the one that directs the heat to the floor or to the defrost or the vents. The temperature is controllable so we know the "blend door" is OK, but we have little or no heat to the floor. It's a $15 part and $485 in labor since the front fender, hood and dash have to come out to replace it. At 10 years of age and 329K miles, it's still a more than serviceable vehicle, if not for this heater issue, but we would rather not dump another $500 into this door deal. I have looked at the schematics and wonder if there is some way to get at that flapper door to prop it up to allow heat to the floor area. I'm hoping that I can identify the lower box on the driver's side and carefully drill a hole that would allow me to stick a piece of coathanger, etc up to get that door up. The door's spindle is probably broken, which is what has been the case in the previous replacements. The vacuum elements are not the issue. I am working from the dealer's schematic put out by ProQuest Automotive EPC and the lower heater box that I am contemplating drilling is, I believe, # 11, in the area over the part that's labeled 14. Any help with this would be appreciated. I'm the 'house' mechanic (resp. for a 69 xk-e, 67 & 81 corvettes ">& 47 Chris Craft), so will understand any directions that are provided.
#60 of 154 Heater problems
Dec 29, 2007 (7:48 pm)
I have a 1997 Chevy Blazer with a heater that only seems to work when it wants to. One day it will work just fine and the next day nothing at all. It gives no warning and I have not heard any unusual noises....it's not only the heater, it's cold air too, when I turn it on nothing happens. But I can go out a couple days later and turn it on and it works fine. Any suggestions as to what the problem could be?
#61 of 154 Re: heating issues - 2001 Blazer [toolzz]
Dec 30, 2007 (9:20 am)
Sorry I've been away for Christmas. It was Pete at Folsom Lake Dodge in Folsom CA.
#62 of 154 Blazer heat/cool problem
Dec 31, 2007 (5:42 pm)
I'm guessing when you say nothing happens you mean the blower doesn't run. If that true the control on the dash for blower speed may be worn out, the wires to the blower may not be making a good connection or the balast resistors may be broken or not making good connection. I suggest when you have the problem you check the voltage at the dash blower speed switch both in and out. The switch connects to the blower and balast resistors which switch in more or less resistance to slow the blower down. Next I would check the voltage at the blower motor. The blower is in the engine compartment. If there is voltage at the motor but it's not runing, check that the motor is grounded by hooking a seperate wire from a clean spot on the frame to the battery negative terminal or you could measure the voltage on the fram. If it's not grounded the frame will have a voltage on it and it should be zero.
If there is voltage at the control but none at the blower, check the resistors. They stick into the air passage between the blower and the heater core. It should be connected with a plug and I believe the resitors are on a plate that can be removed.
The blower, resistors and control are all replacable parts.
#63 of 154 1998 S-10 blazer Msg 59 update HEAT AGAIN
Jan 13, 2008 (9:58 am)
Ok, so we spent some quality time with the '98. First I went to the local Chevy dealer where the parts mgr was kind enough to give me copies of the exploded diagrams for this heater box flapper/valve/door system. It turns out that the issue for this problem centers on the 'valve' that is on the left side(driver's) side of the heater box. Due to the number of times that this dash assembly has been in and out of the SUV, a small section of the trim around the floor vents was cracked and so, easily removed so that I could see up inside. There didn't appear to be any problems with the vacuum hoses or assemblies. The goal was to get this horizontal door that allows heat to the floor ducts to open up. What the H, I took a pair of very long (straight section about 8 inches) needle nose pliers with a 45 degree angled nose and stuffed the angle part up the ducts to try to push the door open. Guess I was living right... heat on the floor!!!!!!!!! Jubilation only lasted until the next day when the same problem reoccurred. This time after pushing the door up and open, we took a piece of form wire and put a long loop in it, with the diameter of the loop about 3/4 inch. The long length of the loop was so that the raw end didn't get caught on anything and wire was used to be able to shape it to follow the contour of the duct UP to the door/valve. We did not (fortunately) ever have temp problems. The current size of the loop end creates an opening that is ok for heat supply. More supply could be created by making a larger loop end and thus holding the door farther open. You could probably recreate this repair even if the trim is not broken out like ours was; you just need to be able to stuff a loop of wire up the duct to push the door open. We made sure to disconnect the battery while we were working in there, even though it doesn't appear (from the diagrams) that there is anything electrical involved. (Be sure to have your radio reset code). We are guessing that what was happening was that this door was falling down into the opening that it was designed to close off, either through wear or a worn seal. The motor drive didn't have enough power to pull it up out of the stuck position and thus the cheap plastic drive assembly broke. So we saved ourselves a $500 repair bill, but then our house furnace's blower motor died. Guess there's just no winning some days!
#64 of 154 2005 blazer heating problems
Jan 21, 2008 (5:06 am)
I have a 2005 blazer and my heater doesn't work it worked fine one day and the next it doesn't can some one please help me out
#65 of 154 Blend Door Actuator
Feb 27, 2008 (7:54 am)
Recently I had the joy of replacing my heater core in my 1999 Chevy Blazer. After having everything put back in I realized that I had one part and 3 screws left over. Well, after the first cold night I realized that the part I left off was my BLEND DOOR ACTUATOR. So my question is where does it go, how do I put it back in, and can I do it with out having to take the dash board apart again? Please help I have to do as much of my own vehicle work as possible due to the fact I am a preacher so I do not have alot of money.Thanks
#66 of 154 Re: Blend Door Actuator [ccfrazier2]
Mar 03, 2008 (4:53 pm)
The blend door goes in the duct between the AC and heater core. It flips back and forth to blend hot and cold air even whe the AC isn't running to control the temp. That's wat the actuator does. Yes you probably do have to take the dash apart unless you can get to the place where the actuator goes. In my 96 you can't.
Go to the parts counter at the dealer and they will copy the pictures and be sure to get the list of the descriptions. They will give it to you for free. You should be able to identify 3 flaps or doors. You should be able to see the one that goes between the hole for AC and heater. The actuator is connected to the shaft of the door and bolts to the duct. The pictures from the parts catelogue will show where it goes.
#67 of 154 Re: Heater problems [dm2785]
Mar 07, 2008 (10:38 am)
Have a 1997 Chevy Blazer, my heat will not turn on when i put the switch on at all. Like other trucks it will work when it wants to and then couple days later i will get in it and it will work all on its own any ideas as to what the problem is.