Truck heater problem-HELP please

Hi,
I have a 96 chev regular cab,350 vortec,equipped with air conditioning.
Recently the heater blower fan quit working on the first 3 speeds,the high
speed still works fine but the other speeds aren't working at all.
I replaced the blower fan motor but still only high speed works when I turn the controls.
Any help would be really appreciated! Thanks
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I think there are some relays or relay behind the glove compartment that control the fan speeds.
On Tue, 30 Dec 2003 01:17:02 GMT, "CBConsulting"

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Elbert Clarke
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Truck heater problem-HELP please Group: alt.autos.4x4.chevy-trucks Date: Tue, Dec 30, 2003, 1:17am (CST+6) From: snipped-for-privacy@hotmail.com (CBConsulting) Hi, I have a 96 chev regular cab,350 vortec,equipped with air conditioning. Recently the heater blower fan quit working on the first 3 speeds,the high speed still works fine but the other speeds aren't working at all. I replaced the blower fan motor but still only high speed works when I turn the controls. Any help would be really appreciated! Thanks
True there is something next to the fan motor....Its not a relay how ever but a resistor....Theres a electrical connection and its held in by 2 or 3 5.5mm screws......Pull it out it has a green coating on it you will see it burnt or the coating peeling off there is your problem.....Very common problem..... When replacing it you will et a updated one which is black and seem to last alot longer....
Steve C
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Thanks for the help-much appreciated!
(CBConsulting)

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Steve,
I have the same problem on my 91 GMC. Fan only blew on HI for awhile and then stopped working altogether, after a burning smell (like burning wire) filled the cab. Now heater doesn't come on at all.
I checked the fan motor by putting power directly to it and its OK. I'm going to swap the heater control unit on the dash with a 90 Chevy to see if its OK.
The dealer sold me a resistor block which wasn't right next to the blower assembly as they said but about 8 inches to the left on the top of the housing. Both the existing one and the new one were bare metal (one coil, one straight wire with a thickened barrel in the middle). The existing one was a little discolored, but still intact.
There is something to the side of the blower motor (to the driver side, not directly behind) right up against the firewall, where it is almost impossible to remove. Is this the unit you mentioned in response to the previous post with the green insulation?
Thanks Ian
(CBConsulting)

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Gm has like 4 different type resistors....the one in question has a wire that plugs in directly to the fan motor.....I changed one out yesterday and the new one i put back in was a totally different style.than what was in it ... On the 91s they had resistors but started faseing out the new ones come with modules....Did you change out the resistor?If you smelled something buring after you put it in you need to trace you wires and check your connections .....When you pull your control head you will more than likely see if it got burnt....But on older models fan dont work likely the control head or you fan motor....fan works on high and no other speeds resistor or module..... Steve C
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Another thing You said you smelled burt wire in the can then it stopped working....Said gm sold you the resistor...ok did you put it in? Also after you put it in did you test your lead from the control head for power?And might sound funny but did you check the fuse?
Steve C
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Steve. Thanks for the feedback. I pulled the controller from the dash and took it apart; there was no sign of burning anywhere.
I checked the "resistor block" the dealer sold me. It looked OK (a little discolored) so I didn't replace it, but I'll do that now. It is two wires: is a straight wire with a widened part in the top; the other is a coil like a heater element. Both are bare. But it wasn't next to the blower motor as my Haynes book (and the dealer's schematic) shows. Another dealer's schematic showed it on top of the main heater housing about 8" to the toward the driver's side.
However, there is some kind of module that looks like the description you gave; as far as I can see it. It is attached to the side of the housing that the blower motor sits in and I can feel a wire going over the back and down to it. Trouble is, I can get one screw out and can feel at least one other. If I can get to the others, I don't see how I'll ever get it back in. So I'm trying to remove the housing for the blower motor so I can get to it. Otherwise, it looks like I'll have to remove the whole heater assembly. But it sounds to me like you didn't have to do anything like this. So I was wondering if I'm missing something (probably obvious) that will make this a lot easier to do. Any info on this would sure be appreciated.
I'm also checking the wiring back from the controller looking for power loss, or any evidence of burning.
We just got a bunch of snow and my van sure isn't like my truck. Murphy's Law.
Thanks, Ian

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Top post.... Yes it is in the same housing the blower motor is in ....And I know the screws are a pain....We usually us a 5.5mm swivle head socket all you need to put back is the two in front we never put the on in the back in....You should be able to see the module as you look into the fan hole...Eventually the screws come out my take longer than you think it should but we all who have replaced them have been there....There is a plug to te module and from the module is a plug for your fan motor....That is what controls your speed.... Steve C Re: Truck heater problem-HELP please Group: alt.autos.4x4.chevy-trucks Date: Sat, Jan 3, 2004, 10:22pm (CST+6) From: snipped-for-privacy@shaw.ca (Ian) Steve. Thanks for the feedback. I pulled the controller from the dash and took it apart; there was no sign of burning anywhere. I checked the "resistor block" the dealer sold me. It looked OK (a little discolored) so I didn't replace it, but I'll do that now. It is two wires: is a straight wire with a widened part in the top; the other is a coil like a heater element. Both are bare. But it wasn't next to the blower motor as my Haynes book (and the dealer's schematic) shows. Another dealer's schematic showed it on top of the main heater housing about 8" to the toward the driver's side. However, there is some kind of module that looks like the description you gave; as far as I can see it. It is attached to the side of the housing that the blower motor sits in and I can feel a wire going over the back and down to it. Trouble is, I can get one screw out and can feel at least one other. If I can get to the others, I don't see how I'll ever get it back in. So I'm trying to remove the housing for the blower motor so I can get to it. Otherwise, it looks like I'll have to remove the whole heater assembly. But it sounds to me like you didn't have to do anything like this. So I was wondering if I'm missing something (probably obvious) that will make this a lot easier to do. Any info on this would sure be appreciated. I'm also checking the wiring back from the controller looking for power loss, or any evidence of burning. We just got a bunch of snow and my van sure isn't like my truck. Murphy's Law. Thanks, Ian
Another thing You said you smelled burt wire in the can then it stopped working....Said gm sold you the resistor...ok did you put it in? Also after you put it in did you test your lead from the control head for power?And might sound funny but did you check the fuse? Steve C
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