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I have a 97 Blazer that the blower motor is not working. So

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I have a 97 Blazer that the blower motor is not working. So I got a replacement from the junk yard and after 3 hours of install, found out that my problem was not fixed. Did I get a faulty motor or is it something else? The fuse is good. and the 2 wire plug in to the blower motor has power when I turn it on.      Thanks in advance, Bob
It sounds to me like you have done some wire testing here. Does the purple wire have 12 volts in the high speed setting? Is the black wire a constant ground wire?
Customer: replied 8 years ago.
I used a cheap multi meter. It appeared to have 11 volts (purple pos. & black neg.). I did not get any difference when switching between high and low speed fan settings.
If you have voltage to this point, the blower motor should be operating. I would replace the blower motor once again. You may want to try the next one to verify it works before going though the trouble of making this swap. Feel free to contact me with any questions! Good luck!
Customer: replied 8 years ago.
could it be the resistor pack? Just want to be sure before buying another motor.
if you have voltage at the motor and its not running, this could only be the blower motor. Keep in mind that on the high speed the voltage bypasses the resistor and is powered directly from the blower relay.
Carhelp4u and 4 other Chevy Specialists are ready to help you
Customer: replied 8 years ago.
I got a new blower motor for the blazer, it still does not work. I retested the voltage at the plug, it reads about 10 volts. The power is only present when the heat/ac is turned on and the voltage does not change if I adjust the blower speed. Any other ideas?
Do you have a good ground at the blower motor?
Customer: replied 8 years ago.
I checked it with an ohm meter, I have a good ground.
Customer: replied 8 years ago.
I picked up a new blower resistor pack in hopes that it is the issue. I haven't gone looking for it, I assume it is under the glove box, correct?

I have been chatting with a few other experts on this one and I got to say that we are somewhat confused by all of this. The 10 volts you are getting at the blower plug should be enough to operate the motor. As fas as the resistor goes, its out under the hood on the heater case. Here is what must be done to replace this unit.

  1. Disconnect the negative battery cable.
  2. Remove the A/C control relay bracket with the relay.
  3. Remove the blower resistor harness.
  4. Remove the stud from the dash panel, if necessary.
    Object Number: 281206  Size: SH

  5. Utility only- Cut the access cover (1) from the case.

    Cut all four sides of the cover in order to remove the three attaching screws. Use a sharp utility knife in order to cut the case. Make the cuts straight and clean because you must reinstall the access cover and the access cover must be visible to the customer.

  6. Remove the blower resistor.

  7. Object Number: 281206  Size: SH

  8. Install the blower motor resistor.
  9. Utility only- Apply a bead of black weather-strip adhesive over the cut-line areas (1).
  10. Utility only- Allow the adhesive to set for 15 minutes, or until the adhesive skins over.
  11. Install the stud to the dash panel, if necessary.
  12. Install the resistor harness.
  13. Install the A/C relay bracket into the body.
  14. Connect the negative battery cable.
Customer: replied 8 years ago.
OK, no good. I replaced the resistor. I am getting 12 volts at the plug. but still no blower action. I checked the new blower by wiring direct to the battery and that works. Ahhhhhg!!!! OK I rechecked the ground, black wire to alternator housing 0 ohms. Just for giggles, truck off, no power at plug, purple wire (hot) to alternator housing also 0 ohms, is this right????
Boy something is not right here. I am wondering what happens if you make another temporary ground for the blower motor. The testing you are doing should allow for this motor to operate. The blower motor should have ran on the 10 volts.
Customer: replied 8 years ago.
Tried it, didn't work. I think I have a short somewhere. I have 0 ohms between positive and negative. How can I tell where.
OK I understand your testing now. Does this resistance on the hot side go away when you unplug the blower motor resistor?
Customer: replied 8 years ago.
yes, when I unplug the resistor the hot wire shows no connection to ground.
Is the fuse labeled HVAC in the under hood electrical center or the fuse labeled HVAC #9 in the instrument panel fuse box blown? Does this happen no matter what speed you have selected?
Customer: replied 8 years ago.


Powered up

REsistor unplugged.

blower on high 0 ohms

blower on low no connection


No fuses under hood, instrument panel fuse is good.

You won't show the short on low as the resistor is not plugged in. What really is making me wonder is that you verified 10 volts then 12 volts at the blower motor connector. If this is the case and this voltage is being shorted, It should be blowing the fusible link (I did mispeak, this does have a fusible link rather than a fuse for the high speed). It may be worth a shot to verify if you do in fact have voltage at the red wire of the high speed blower relay. Here is a better illustration of this.


Here is where the relay is located.

Object Number: 531763  Size: MF

(1)Blower Motor and Connector
(2)Blower Motor Relay
(3)Blower Motor Resistor and Connector

Customer: replied 8 years ago.

yes I have power at the red wire of the relay. nothing else has power.


At the relay the purple wire that goes to the blower has no connection if unplugged from motor and 0 ohms if motor is plugged in.


I hate electricity!!!

Customer: replied 8 years ago.

OK wrapping up for the night.


Put everything back together, plugged everything back in and guess what worked. Yup, blower worked. I have no idea why. I am afraid by jiggling some wires things are working (did I mention I hate electricity). I think maybe by messing with the relay. I am planning on replacing the rely for the sake of doing it. What do you think?

You very well may be onto something. I just cannot see you having a grounded power wire without blowing the fusible link, or the fuse that powers the resistor. You cannot have voltage and a ground on one wire.