70 Skylark heater switch is reversed

Discussion in 'Sparky's corner' started by Paul Massicotte, Sep 29, 2019.

  1. I recently swapped my factory dash bezel out for a Parts Place repop. In doing so, I replaced my heater control unit with one that had two good slides with the chrome ends.
    Anyway, when I replaced the unit I swapped my existing heater switch into the new plastic unit and now it’s reversed. Off is High and High is off. The 3/2 staggered plug can only plug in one way. I tried another switch (from the swapped in unit) and it too blows in reverse.

    Any ideas?
  2. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    Easy fix. Flip the car on its roof.
    john.schaefer77 likes this.
  3. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Make sure the connections to the high speed relay on the firewall are correct. Maybe it's plugged in wrong. That relay controls max fan speed.
  4. I can check, but I literally swapped the dash bezels and heater switches in an hour. Was working normal then an hour later it was flipped.
  5. Skyhawk

    Skyhawk Well-Known Member

    Make sure the wires on the blower resistor are on correctly.
  6. buick64203

    buick64203 Just plum crazy Staff Member

    You have the switch in upside down. On a non AC heater control, the switch fits both ways. The plug should be on the slide side if its in correctly
  7. If I flip the plug over there will be at least one blade on the control that’s not connected. That’s correct?
  8. buick64203

    buick64203 Just plum crazy Staff Member

    Im not talking about flipping the plug, unscrew the two 1/4" screws and flip the whole switch. Its in upside down
  9. It's attached to an L shaped bracket. It only mounts one way. I'll take a photo tonight.
  10. buick64203

    buick64203 Just plum crazy Staff Member

    The plug should be inboard on the back of the heater controls. If it's upside down, the plug will be outboard of the controls.

    It actually fits both ways on a non AC control
  11. Jason, you're correct. Despite the L bracket shape, it's in backwards. And now the dash has to come out.....again.

    Thanks for filling me in.
  12. buick64203

    buick64203 Just plum crazy Staff Member

    Aaah....light dawns on Marblehead :D:D:D:D

Share This Page