no heat/air conditioning

jiminpa · 09-20-2009, 08:03 PM

my 2000 sierra has decieded to stop all air movement thru the cab.no heat or a/c regardless of the settings.hoses are hot on the heat side,cold on the a/c side.i think its in the cabinet(a door not switching?).help!!

hotrodpc · 09-20-2009, 09:40 PM

Sounds to me like its possibly a fan or fan relay of some type. So the AC is cooling the coils, but not blowing air across them. Would be the same for heat. Your heater core will get hot, but no fan to push air.

crabtruck · 09-21-2009, 01:04 AM

Have you checked your 3 HVAC fuses ? 2 inside and 1 under hood.

leolkfrm · 09-21-2009, 05:35 AM

if what you are saying is the fan does not work, i'll bet the resistor and plug are bad in the blower box......you will see it next to the blower motor

jiminpa · 09-21-2009, 08:10 AM

fan works good,all 3 speeds.but nothing gets hot or cold out of the vent.

bradrhale · 09-21-2009, 11:49 AM

out of which vent?? what vent are you getting air out of and are you getting any air out of anything other than that one vent?? can you switch to defrost, dash and floor, or just one??

jiminpa · 09-21-2009, 12:04 PM

it doesn't matter,they all work(the vents) with the fan.on heat it doesn't get hot,on a/c it don't get cool,just stagnet air.the heat hoses are hot in the engine compartment,as the a/c hose are cold also to the canister.its like its not getting pushed thru the coils.is there a door that switches between coils that could be stuck between areas?

Wyley87 · 09-21-2009, 12:13 PM

could it possibly be the air duct actuators?

bradrhale · 09-21-2009, 03:55 PM

2000 model has a blend door actuator that regulates flow through the core and evaporator by a blend door. it is possible that it is stuck in the middle position but i would turn on the heat all the way to verify that it is actually mixing the two.
turn the key to on position and put your ear down underneath the dash. alternate the temp knob between hot and cold and listen for the motor to hum. if no hum, than you have a problem with the actuator or selector switch.

jiminpa · 09-24-2009, 12:09 PM

no hum.guess i'll tear into the dash this weekend and see whats up.

09-20-2009, 08:03 PM	#1
jiminpa Full Member Join Date: Jun 2007 Location: mercer co,pa Posts: 13	no heat/air conditioning my 2000 sierra has decieded to stop all air movement thru the cab.no heat or a/c regardless of the settings.hoses are hot on the heat side,cold on the a/c side.i think its in the cabinet(a door not switching?).help!! __________________ 2000 gmc sierra slt 5.3l v8 extended cab 6'box

09-21-2009, 05:35 AM	#4
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,844	if what you are saying is the fan does not work, i'll bet the resistor and plug are bad in the blower box......you will see it next to the blower motor __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

09-21-2009, 08:10 AM	#5
jiminpa Full Member Join Date: Jun 2007 Location: mercer co,pa Posts: 13	fan works good,all 3 speeds.but nothing gets hot or cold out of the vent. __________________ 2000 gmc sierra slt 5.3l v8 extended cab 6'box

09-21-2009, 12:04 PM	#7
jiminpa Full Member Join Date: Jun 2007 Location: mercer co,pa Posts: 13	it doesn't matter,they all work(the vents) with the fan.on heat it doesn't get hot,on a/c it don't get cool,just stagnet air.the heat hoses are hot in the engine compartment,as the a/c hose are cold also to the canister.its like its not getting pushed thru the coils.is there a door that switches between coils that could be stuck between areas? __________________ 2000 gmc sierra slt 5.3l v8 extended cab 6'box

09-21-2009, 12:13 PM	#8
Wyley87 Senior Member Join Date: Jul 2009 Location: Arlington, Tx Posts: 663	could it possibly be the air duct actuators? __________________ 96 GMC C1500 305 2WD K&N FIPK C.A.I. Rebuilt Motor and Trans Mobil 1 15w50/Mobil 1 Filter 05 Nissan Xterra 4.0 V6 Royal Purple 5w30/Mobil 1 Filter Cost money to go fast...How fast do you wanna go?

09-20-2009, 09:40 PM	#2
hotrodpc Banned (temp) Join Date: Jul 2008 Location: OKC, OK Posts: 6,921	Sounds to me like its possibly a fan or fan relay of some type. So the AC is cooling the coils, but not blowing air across them. Would be the same for heat. Your heater core will get hot, but no fan to push air.

09-21-2009, 01:04 AM	#3
crabtruck Senior Member Join Date: Jul 2007 Posts: 4,079	Have you checked your 3 HVAC fuses ? 2 inside and 1 under hood.

09-21-2009, 11:49 AM	#6
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 9,469	out of which vent?? what vent are you getting air out of and are you getting any air out of anything other than that one vent?? can you switch to defrost, dash and floor, or just one??

09-21-2009, 03:55 PM	#9
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 9,469	2000 model has a blend door actuator that regulates flow through the core and evaporator by a blend door. it is possible that it is stuck in the middle position but i would turn on the heat all the way to verify that it is actually mixing the two. turn the key to on position and put your ear down underneath the dash. alternate the temp knob between hot and cold and listen for the motor to hum. if no hum, than you have a problem with the actuator or selector switch.

09-24-2009, 12:09 PM	#10
jiminpa Full Member Join Date: Jun 2007 Location: mercer co,pa Posts: 13	no hum.guess i'll tear into the dash this weekend and see whats up. __________________ 2000 gmc sierra slt 5.3l v8 extended cab 6'box

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