Blower motor fan not running

Discussion in 'The Big Chill' started by leckard, Mar 4, 2019.

  1. leckard

    leckard Active Member

    Cant figure out why the blower motor is suddenly not working. The ground wire is attached well, the selector switches all work for the vents and the ac compressor gets power when selected. The fuse is good for the ac/ heater. Dont think its the resistor because i read here that the fan should still come on in high position even if the resistor is bad. There is suppose to be a feed wire to power the thing somewhere but dont see any going to the housing. Where is the power wire so i can run a jumper to the battery. Also had some work done recently so maybe a wire got broken. What am i missing?
     
  2. buick64203

    buick64203 Just plum crazy Staff Member

    It would help if we knew that kind of car your working on and if it has A/C or not. You should have a +12v wire going into the blower speed selector switch. The selector switch then directs the power though the different resistors to cut down the voltage to give you the low and medium. On high, the blower bypasses the resistor and the blower gets full 12v. Have you checked the connector wit ha DVOM? Does the blower motor work on high? Is the blower capable of working?
     
  3. leckard

    leckard Active Member

    Sorry hate when i forget to list the car. I signed in as a newbie because im not sure of my password because the email i used to use no longer exist. Guess i will have to contact someone to get back in with new password. Anyway, Its a 71 Skylark with ac that did work until recent. So i looked st the resistors and they just sit inside the housing not connected to anything. Is there not another hot wire that connects to the blower motor?
     
  4. buick64203

    buick64203 Just plum crazy Staff Member

    Ok, cool. So the most common issue with blower motors on AC cars is the relay goes bad. Normally when the relay goes bad, it will work on HIGH only. Also what happens is the connections on the relay get rusty, then you get connection issues. Once that happens, the plug melts because resistance generates heat. The blower motor relay is mounted on the firewall near the voltage regulator. Small silver rectangular box with 2 small screws holding it in place.

    First, take the relay off and make sure all the spades are clean. Check the connectors on the wires as well. Reconnect everything and retest. Then get back to us with the results.
     
  5. buick64203

    buick64203 Just plum crazy Staff Member

    Sorry, just re-read your post. Are you saying that the resistor block doesn't have a connector on it?
     
  6. leckard

    leckard Active Member

    Ok thanks. I unplugged the relay yesterday and reseated it but didnt remove it. Also the fan does not work on any setting. Kept it on high. Also yesterday i found a plug connector near the housing that wasnt hooked to anything. I jumped from it to the battery and the relay box started buzzing. Whats up with that. Ill look at everything again this afternoon
     
  7. leckard

    leckard Active Member

    Yes the resistor has a connector that goes into housing om passenger side and the relay also has a connector (silver box)
     
  8. buick64203

    buick64203 Just plum crazy Staff Member

    Ok, keep us posted! Remember, were all counting on you!
     
  9. leckard

    leckard Active Member

    So. Any idea what the plug would be that goes nowhere. It must have something to do with the relay since it caused it to buzz when i jumped it.
     
  10. buick64203

    buick64203 Just plum crazy Staff Member

    Not sure what plug your talking about. A picture would help. If you cant post a picture, describe where it is, what the plug configuration is and what color wires are going to it. I'm pretty familiar with the wiring on the 70-72's so I can usually ID it
     
  11. leckard

    leckard Active Member

    Checked relay and its contacts are clean . Has voltage on single wire to relay. Cant measure any voltage on the other side of relay with 3 wires. Is there supposed to be any?
     
  12. buick64203

    buick64203 Just plum crazy Staff Member

    The three wire connector should have 12v on the red wire
     
  13. buick64203

    buick64203 Just plum crazy Staff Member

    Dumb question- you did check the 25a fuse labeled "HEATER AC" on the fuse block?
     
  14. leckard

    leckard Active Member

    Fuse is good.and checked 3 wires again and there is 12 volts. Probable didnt make contact the first check.
     
  15. buick64203

    buick64203 Just plum crazy Staff Member

    So on the three wire connector. you can jump the red wire to the black with orange tracer. The black with orange tracer wire goes right to the blower motor. The blower motor should start working. If so, your relay is likely no good
     
  16. leckard

    leckard Active Member

    Ok ill try that tomorrow. Thanks .
     
  17. leckard

    leckard Active Member

    Went out and tried the jumper but nothing happened.
     
  18. buick64203

    buick64203 Just plum crazy Staff Member

    You sure you have 12 volts at the red wire?

    Are you sure the wire is connected to the blower motor?
     
  19. leckard

    leckard Active Member

    How would i know if the wire is connected to the blower motor?
     
  20. buick64203

    buick64203 Just plum crazy Staff Member

    You can look under the fender by the hood hinge and see it. Sometimes you can use an inspection mirror and a light.
     

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