Power Window Relay Mod

Discussion in '1973-1987' started by nerfherder78, Feb 12, 2011.

  1. nerfherder78

    nerfherder78 Member

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  2. Chevy1986

    Chevy1986 Member

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    Ohh ok.. I thought they were similar to the regular relay you find in car alarms and accesories. Just a little black square with like 4 or 5 pins..
     
  3. nerfherder78

    nerfherder78 Member

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    I have seen a few generic/aftermarket relays that are designed for power locks/windows, but the generic 4/5 pin relays can't do what the door lock relays do. Activate the relay one way, and one wire is 12v, the other becomes the ground. Activate it the other way, and the wires roles are reversed. You can use generic 5 pin relays like these to do that, its basically what I did to add window relays, but it requires two relays rather than one.

    So your wiring would look something like this:
    1st Relay:
    85 - blue wires from the lock switches
    86 - ground
    87 - power from the fuse block
    87a - ground
    30 - grey wires to the lock actuators

    2nd Relay:
    Relay Wiring:
    85 - black/white wires from the lock switches
    86 - ground
    87 - power from the fuse block
    87a - ground
    30 - tan wires to the lock actuators

    with the orange wires from the switches drawing 12V from the fuse block.

    This way when the relays are active both wires act like grounds. Using the switch will activate one relay, connecting either the tan or grey wires to 12V and powering the actuator. Push the switch the other way and the opposite set of wires becomes 12V while the first stays a ground, powering the actuator in the opposite direction.

    Also note that you might have to swap the tan and grey wires so when you push down on the switch, your doors lock rather than unlock. I'm also getting the wire colors from the diagram, in case yours are different.
     
  4. Chevy1986

    Chevy1986 Member

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    i think i will be better to do like yours,those door locks relay are kinda $$ and i didnt find that many for a good price..i dont mind having 2 relays..
     
  5. Chevy1986

    Chevy1986 Member

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  6. nerfherder78

    nerfherder78 Member

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    Yep, that's a SPDT (single pole, double throw) relay, so it will have the 87 and 87a terminals that you need.
     
  7. Chevy1986

    Chevy1986 Member

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    ok cool,thanks. ill get that and hopefully ill get new pins and hinges next week to install the doors..
     
  8. Chevy1986

    Chevy1986 Member

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    Can't get those relays to work :( ... Maybe I'm missing something lol... I havent install the doors,but I been testing the windows with the battery...
     
  9. Roadhazardguy

    Roadhazardguy Member

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    What do you have the relays grounded to, just the door or did you ground the battery to the door also?


    Also guys I think im gonna go get me some parts later today and do the relay mod to my headlights. I plan on 10ga wire like Nate said then get a couple relays, circuit breaker, blade connectors, then crimp it all together, solder it and cover it with heat shrink. Now my question is will two 30 amp relays be sufficient or should I run 4, One for each beam. Haven't seen anybody else do it that way and im guessing that would be overkill, and I now see them rated for 480w.
     
  10. Chevy1986

    Chevy1986 Member

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    Just got it working last night, my batt. Needed to be grounded, that was the problem :)..

    Why you putting relays for you headlights?
     
  11. vwnate1

    vwnate1 Member

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    Headlight Relays

    I use the tiny Hella / Bosch cube relays , they're rated @ 40 amperes continuous .

    When I worked nights in the Heavy Duty Truck Shop , I hipped the Mechanics to these for the sweepers that always blew bulbs and switches , melted wires etc. on the gutter lights ~ they were amazed such a small relay worked that well .

    You're right on track with the 10 Ga. wire , don't buy cheap wire ~ good wire has more , thinner strands in it ~

    Didja know ? the electricity flows around the outside of each strand so having more strands , makes a wire better able to carry loads ~ that's why welding wire makes the best battery cables .
     
  12. Roadhazardguy

    Roadhazardguy Member

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    I bought everything from oreillys so I figure the relays will do for now but I can always replace them with Bosch later. The wire is 10ga but its not all that fine of strands, it should do alright though. We'll see... I also got the GM 56 style connectors to go back in my stock headlight plugs, I wanted to reuse the plugs because the way they sit flush up against the back of the bulb.

    I got started on it later in evening but I'll finish it up tomorrow after work, hopefully before I go out for dinner for my bday.

    I didn't know that about electricity, how do they figure that out anyway?
     
    Last edited: Apr 11, 2013
  13. nerfherder78

    nerfherder78 Member

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    You wire them in as close and directly to the battery as you can, and they allow the lights to draw power directly from the battery. That reduces the amount of power lost from resistance in the wires and the headlight switch, resulting in more light. Most newer vehicles already have them for headlights, power windows, etc.

    I added relays to mine a few years back when my driver side connector went bad, voltage at the light increased from about 10.5V to about 11.8V. That was with just 2 relays and using most of the stock wiring. Headlights were noticeably brighter. I've since upgraded the wiring to 10ga, they're somewhat brighter, but not much.

    One of these days I need to upgrade the headlights themselves. They work just fine for me... until some new car with blindingly white lights coming from the other direction passes by.
     
  14. Roadhazardguy

    Roadhazardguy Member

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    Well I finally had a chance to finish everything up today and re-adjusted them, they are definitely brighter but now its time for some new lights.
     
  15. vwnate1

    vwnate1 Member

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    Brighter Headlights

    FWIW ;

    You can simply use # 6014 or 6016 seal beams , they'll look the same but have more output , being designed for trucks .

    D.O.T. Legal too ! :) .
     
    Last edited: Apr 30, 2013
  16. nerfherder78

    nerfherder78 Member

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    My brother had the H4 conversion lamps in his '78, but it seems harder to find one for the square '80s headlights. LMC sells them, but I don't know how good the quality is.
     
  17. Chevy1986

    Chevy1986 Member

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    Everything it's working, but not sure why one side of the locks open and other side lock, if the wires were switch at the relays they would not work right?
     
  18. nerfherder78

    nerfherder78 Member

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    Sounds like the tan/grey wires to one of the door lock actuators is reversed. Trace them back to your relay and switch the wires and it should work normally.
     
  19. Chevy1986

    Chevy1986 Member

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    That's what I was thinking, but if they were reverse, would they still work ? I was switching the wires at the relays and nothing..
     
  20. Chevy1986

    Chevy1986 Member

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    You were right, they were reverse!.. I just cut the 2 wires and switch then, not they work fine.. :) ... Thanks..
     

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