Blower Relay location On 68 Skylark

Discussion in 'Sparky's corner' started by Rich Skylark, Mar 12, 2020.

  1. Rich Skylark

    Rich Skylark Gold Level Contributor

    On my 68 Skylark after putting heater control’s back in dash , only have high speed on the fan . Looked at the resistor on the evap box ( car has a/c ) and it doesn’t look burnt . 1) where is the blower relay located ? What should I be checking next in line after the relay ?
     
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    The high speed relay is on the firewall on my 70. That would be high speed though, which you have. The resistor can be bad even though it looks fine. Check the wiring to it as well.
     
  3. Rich Skylark

    Rich Skylark Gold Level Contributor

    How would I check the resistor is good ?
     
  4. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Multi meter set to Ohms.
     
  5. Rich Skylark

    Rich Skylark Gold Level Contributor

    Will do Larry
     
  6. Rich Skylark

    Rich Skylark Gold Level Contributor

    I ohm’d out the resistor on the evap box and the resistor’s all showed good . I remembered I had another blower switch from a previous GS I’d owned and tried that one with the same result, high speed only. With voltage tester the only wire w/ the key on I’m getting power to is the black / orange one . Also looked on the firewall under the hood and don’t see the relay . The wires connected to the resistor ( blue yellow green light blue ) go directly into the grommet to inside .
     
  7. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Yeah, like I said, on the 70, it's almost dead center on the firewall next to the vacuum storage container.

    https://www.rockauto.com/en/moreinfo.php?pk=532141&cc=1379763&jsn=399

    Rockauto doesn't list one for the 68.

    That tells me that you should consult your 68 Buick Chassis Manual, you have one, right?:)

    https://www.ebay.com/itm/Vintage-19...528339?hash=item5930020613:g:fVcAAOSwHkZdMPvB
     
  8. Rich Skylark

    Rich Skylark Gold Level Contributor

    Yes Larry your correct as usual the 68 doesn’t show one on schematic. I’ve seen them listed 1968-1972 on rock auto and a few others as well .
     
  9. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    They don't list them at all for 68 and 69. So if there is no relay in your wiring diagram, you either have an open in the resistor(s), or a wiring break somewhere.
     
  10. Rich Skylark

    Rich Skylark Gold Level Contributor

    Going to try checking volts from the switch to the resistor. I think the blk/ orange is for the high speed and the brown wire supples power to switch. I’m not sure which speeds the remaining wires control . Any other diagnostic advice keep it coming . Thank you
     
  11. buick64203

    buick64203 Just plum crazy Staff Member

    On an AC car, if you have high speed only, it's usually the relay. The high speed setting runs straight 12 volts to the blower and bypasses the relay.
     
  12. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    I thought it was the exact opposite, if you DIDN'T have high speed, it was the relay. The other speeds run through resistors for each lower speed.
     
  13. Rich Skylark

    Rich Skylark Gold Level Contributor

    I checked the voltage at the resistor and all 4 contacts are getting 12V with the blower on high speed . I’m getting 0Volts on all other speeds . At the switch on max speed I’m getting 12V on the brown wire with switch in all positions as well as the tan wire that’s connected to the a/c clutch control switch. Click down to high still getting power to the above 2 but the lt blue is getting 12v now . Click down to medium the blue goes to 0 V ‘s and the yellow goes to 12V along with the Brown and tan . I did the above tests with both switch’s with the same results . I’m back at it tomorrow
     
  14. Rich Skylark

    Rich Skylark Gold Level Contributor

    4438EF0D-9680-4D79-BE80-81903AC75377.jpeg Update changed the resistor with no results. With key on the brown ( feed from fuse box) show 12 V. At low speed again only the brown feed is hot . On medium speed the tan wire from a/c clutch also shows hot . On the medium speed the yellow is hot as well . When I go to high speed the blue wire joins the brown & tan but the yellow wire goes to 0V . Lastly on maximum speed ( the one that works ) the brown, tan , and now the orange/ black are hot while blue & yellow show 0V’s . All tests done with 2 different switches with same results . All 4 resistor terminals show 12V when max blower speed is working. I’m posting the wiring diagram from the manual . Maybe someone can see something I’m missing from
     
  15. buick64203

    buick64203 Just plum crazy Staff Member

    Rich- is thus a factory ac car or a non ac car?
     
  16. Rich Skylark

    Rich Skylark Gold Level Contributor

    Factory a/c Jason
     
  17. buick64203

    buick64203 Just plum crazy Staff Member

    Swap out the relay and clean the contacts
     
  18. buick64203

    buick64203 Just plum crazy Staff Member

    Try this one rich-

    20200319_221042.jpg
     
  19. Rich Skylark

    Rich Skylark Gold Level Contributor

    Will do if I can find the relay . Searched for one the other day under hood, inside car with no luck. . I read some where that 1969 was the first year these cars used a relay
     
  20. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Take the dash pad off and look on the inside of the metal dash. I know the horn relay is there on some years. Maybe there is another relay there although I do not see a relay in the diagram Jason posted.
     

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