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Gary
Gary, Chevy Technician
Category: Chevy
Satisfied Customers: 15709
Experience:  15 years GM master tech
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I have a 2004 Chevy silverado my A/C & heater don't blow air

Customer Question

I have a 2004 Chevy silverado my A/C & heater don't blow air at all. I replaced the blower resister and the old one was burned the connectors don't appear to show ant indications of defectiveness.But I'm still not getting any air from my A/C or heater. What other possible problems could be causing my A/C & heater vents to not blow air?
Submitted: 1 year ago.
Category: Chevy
Expert:  Gary replied 1 year ago.
do you have a multi meter on hand ?
Customer: replied 1 year ago.
No but my brother did a test with one says it indicated getting some power to the blower he didn't say how much power but he wonders how much power should there be?
Expert:  Gary replied 1 year ago.
at the blower resistor there should be a red and a purple/white and 2 blacks and a purpleone black and purple go to the blower motorwith the truck ON and the blower set to high speed does the red show 12 volts at the resistor ?does the purple show 12 volts ?
Customer: replied 1 year ago.
What I have is the plug from the resister going to the blower is Black & Red. The plug going into the resister are Red, Orange, Black, Blue, Purple, Yellow,and Tan. and I have no idea how to use a multi meter.
Expert:  Gary replied 1 year ago.
ok we have to see if the red shows 12 volts at the resistor and when the blower is set to high speed if the orange shows 12 volts at itcan you also see if the fuse called HTR/AC a 30 amp fuse in the INSIDE fuse box is blown ?that may have blown when the old resistor melted
Customer: replied 1 year ago.
I checked the 30amp fuse HTR/A/C it's good I also checked 10amp HVAC 1 and under the hood the 40amp for the Blower there all good. I even tried turning the key and the control switch to 3 and rap on the Blower with a cresent wrench to see if it would start up and it did not. I still don't understand about using the multi meter, I don't know where to stick the probes.
Expert:  Gary replied 1 year ago.
the truck needs to be on and the blower set to high speedset the meter to DC volts and under the hood connect the red lead to the positive battery and the black meter lead to the negative battery cable will the meter read close to 12.0 volts ?
Customer: replied 1 year ago.
The multi meter is a digital type under DCV it starts from 200m, 2000m, 20,(###) ###-####what should I set it at?
Expert:  Gary replied 1 year ago.
try 20 and see if it will read close to 12 volts if not switch to 200 and see what it reads
Customer: replied 1 year ago.
At 200 I get no reading 00.0 at 20 I get up as high as 14.5-14.23 and as low as 4 and it just fluctuates but then I have a little trouble holding the probes still.
Expert:  Gary replied 1 year ago.
ok with the truck still on and the heater set to high get to the resistor and see if the red and orange show 12 voltsthe red meter lead to the red terminal in the connector and the black meter lead to the block wire terminal in the connector see what it read then move the red meter lead from the red wire terminal to the orange wire terminal what will it read ?
Customer: replied 1 year ago.
I'm sorry I don't quite follow you there, do I need to disconnect the resister? If so where do I stick the red probe from the multi meter and the black probe?
Expert:  Gary replied 1 year ago.
yes unplug the resistorred probe to the red wire terminal and black lead to the black wire terminal
Customer: replied 1 year ago.
I just talked to my brother he said he did that test and it tested at 11. something he believes it's the blower motor not kicking in
Expert:  Gary replied 1 year ago.
ok the red shows 11 voltswhat does the orange read with the truck on and the blower set to high ?the terminal and connector are not melted at all are they where the orange wire terminal is in the connector ?
Customer: replied 1 year ago.
Thank you Gary I hate to just leave you now I know your trying to help but I got to go I'll have to check later hopefully I can get back with you and not get someone else and have to explain everything all over.
Expert:  Gary replied 1 year ago.
just reply back through this postin a nut shell if the connector is in GOOD shape and not melted especially the orange wire terminal and both the red and orange show 12 volts and the black NOT going to the blower motor is a good ground and the resistor is brand new that should mean with the truck on and blower set to high the purple wire at the blower should be 12 volts and the black at the blower should be a good groundif you show that the blower motor itself is badif the orange and red are good and the purple does NOT show 12 volts at the blower then the resistor is defective OR the connections or terminals in the connector are bad ( usually melted a bit ) then replacing the connector for the resistor should correct this issueyou can always get me right back through this post for any follow up for free even after you rate us here at Justanswer

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