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2006 chevy trailblazer_ls
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Discussion Starter · #1 ·
My girlfriend has an 06 Trailblazer LS that she bought from Carmax back in January 09. It has had a few problems over the past few months but nothing serious until now; the other day when she turned her A/C on, it was working then it stopped for an instant before restarting again. She parked to run an errand and when she left, she turned the A/C back on only to find it wasn't working. I had a look at it when she got home and it's not the A/C that isn't working (you can hear the compressor when you turn it on) but the blower as no air comes out whether the A/C is on or not.

I have looked around on the boards and have found that the most common cause for this problem is the blower resistor under the glove box. This morning I had a go, unscrewed the plastic "kick plate" and let the dash down. I hooked a meter up to the blower motor while the car was running; I then had a friend turn the blower on so I could see if any power was getting to the motor - 14V at every speed 1-5. Now does this mean that it could still be the resistor pack (I don't see how seeing as the motor is getting power from the battery) or is it in fact the fan?

If someone could let me know it would be greatly appreciated because SC in July with no A/C is a bit hot and I don't want the girlfriend to shrivel up!

Thanks,

Patrick
 

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2003 gmc envoy_slt
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My girlfriend has an 06 Trailblazer LS that she bought from Carmax back in January 09. It has had a few problems over the past few months but nothing serious until now; the other day when she turned her A/C on, it was working then it stopped for an instant before restarting again. She parked to run an errand and when she left, she turned the A/C back on only to find it wasn't working. I had a look at it when she got home and it's not the A/C that isn't working (you can hear the compressor when you turn it on) but the blower as no air comes out whether the A/C is on or not.

I have looked around on the boards and have found that the most common cause for this problem is the blower resistor under the glove box. This morning I had a go, unscrewed the plastic "kick plate" and let the dash down. I hooked a meter up to the blower motor while the car was running; I then had a friend turn the blower on so I could see if any power was getting to the motor - 14V at every speed 1-5. Now does this mean that it could still be the resistor pack (I don't see how seeing as the motor is getting power from the battery) or is it in fact the fan?

If someone could let me know it would be greatly appreciated because SC in July with no A/C is a bit hot and I don't want the girlfriend to shrivel up!

Thanks,

Patrick
You may need the blower motor itself. Try jumper wires to see if the motor works.
 

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2009 chevy
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6,513 Posts
I then had a friend turn the blower on so I could see if any power was getting to the motor - 14V at every speed 1-5. Now does this mean that it could still be the resistor pack (I don't see how seeing as the motor is getting power from the battery) or is it in fact the fan?
Ok, Patrick, the LS should have the manual HVAC (not the auto digital unit); so, your speed is controlled by a resistor unit. The resistor (the size selected by the speed knob) and the motor form a voltage divider circuit. With a completed circuit, the lower speeds should provide a lower voltage at the motor terminal.

However, for this circuit to function properly, a ground is required.

For you to read full battery voltage at the motor terminal, the circuit is open between the test point and ground.

You can do 2 things to check. Using your volt meter, see if there is any voltage on the motor ground terminal when you have voltage on the motor hot terminal. If you do, you have a bad ground. If you don't, you have a bad motor.
If it is the ground, that circuit completes through the speed control resistor unit, so it could still be a bad resistor unit.

mine is workin on every speed but 5 and i donno what to do either:mad:
dirtslinger, you have a manual HVAC as well. Check fuse # 44 under the seat. If it's good, you need the resistor unit.
 

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2006 chevy trailblazer_ls
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Discussion Starter · #9 ·
"You can do 2 things to check. Using your volt meter, see if there is any voltage on the motor ground terminal when you have voltage on the motor hot terminal. If you do, you have a bad ground. If you don't, you have a bad motor.
If it is the ground, that circuit completes through the speed control resistor unit, so it could still be a bad resistor unit."


That's what I was thinking when I tested it, I didn't think it should read the same voltage no matter what the setting of the blower. I don't see how to take the motor out, well at least the "casing" surrounding it so I can use the motor as the ground terminal; there's an orange screw that I thought released the casing and allowed access to the motor but it's impossible to losen it? Any ideas?

Thanks.
 

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2009 chevy
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6,513 Posts
The reason the voltage does not change, is because there is no current flowing through the resistors.

I've not had mine apart, but you found a battery terminal on the motor, is there a ground terminal that you can access?

If you have voltage (14 v) at this terminal, the ground is open. No voltage, the motor is open.

Is there a ground terminal at the motor?
 

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2006 chevy trailblazer_ls
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Discussion Starter · #11 ·
I assume there is but you know what assuming does. I have tried to get access to the motor but it's behing a "casing" and I don't see how to get it open. There's an orange screw that obviously has something to do with it but it won't budge an inch....if I could get that open then I can see if the motor is working either by hot wiring it or by testing it with a meter.

If anyone can tell me how to open the blower motor casing, it would be greatly appreciated.
 

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2006 chevy trailblazer_ls
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Discussion Starter · #12 ·
Finally managed to get into it all and trasnpires it was a wire that had broken loose from the motor - reattached it and presto, it works! thanks for all the help guys!! :thx
 
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