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Thread: Help Need a workaround for an NLA Overdrive relay

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    Help Need a workaround for an NLA Overdrive relay

    My O/D relay took a crap and so I need to find a work around to get my O/D functioning again since the relay is NLA. Can I jumper wires in the harness that attach to the relay so that I am able to restore O/D? If so which terminals need to be jumped to make this happen?

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    Re: Help Need a workaround for an NLA Overdrive relay

    deleted

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    Re: Help Need a workaround for an NLA Overdrive relay

    What does that mean? "deleted" Could you elaborate please

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    Re: Help Need a workaround for an NLA Overdrive relay

    Realized after posting that my reply was unhelpful, as I misread the problem, then couldn't find the "delete post" button.

    Is there something special about that relay.

    If memory serves, the basic reason to use a relay is to use a low draw circuit to turn on a high draw circuit, protecting the switch and wiring from the higher current load.
    At least that why/how we used relays, back in the day, for driving lights and such things.
    4 pin and 5 pin relays were standard fair
    (things may have changed in the past 40 yrs, though)

    Seems like you should be able to cobble something together.

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    Re: Help Need a workaround for an NLA Overdrive relay

    Here's a copy/paste from another thread:

    Quote Originally Posted by timsrv View Post
    Here's a simple schematic of the overdrive system for the 2wd vans:



    As you can see from the schematic the OD circuit becomes live whenever the ignition is on. The thermo switch and the OD switch are there to disable it. The relay contacts (between terminals 1 & 2) are normally closed (constantly supplying power to the solenoid). When ground is applied to either pin 3 or pin 4 (via the switches) the contacts will open, removing power from the solenoid. When you have power to the OD solenoid the OD should work. If the solenoid has power but the OD doesn't work, then the solenoid is bad.

    If there is power to pin 2 but not pin 1 then the relay is preventing OD operation. If this is the case, then check for ground at pins 3 & 4. If no ground is present at either of these pins but no continuity between pins 1 & 2, then the relay is shot. Make sense?

    For more information on troubleshooting go to the electronic service manual start testing components. The OD section starts on page AT-14 (PDF page #310). If you don't already have it, here's a link to download: https://drive.google.com/file/d/1q4u...7wOD7nKyF/view
    As shown above, the relay is only there to disable the OD if the van is cold or the switch is off. If you don't have a need to turn off the OD and if you don't care if it shifts into OD when the van is cold, then it would be easy to bypass. Just cut the red/blue and black wires off and connect them together.

    If you want it to function as normal, you could use a Bosch relay (you'll need the one with 5 posts) and a couple of diodes. Just ignore the N.O. post and wire it to match the diagram above. If that's too much trouble you could always try one of those salvage yard parts finder places. Good luck. Tim

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    Re: Help Need a workaround for an NLA Overdrive relay

    Thank you Tim. I am fine with the workaround of just having full time O/D it seems they have gone away from the O/D button on the shifter as I really have not seen that on any Toyota made in the last 20 years or more. I guess actually that is not true; the option just morphed into another gate on the shifter instead of PRND2L there is PRND321 which I suppose is better its a physical shift instead of a solenoid doing it for you that can fail but then transmissions these days all use internal solenoids in the valve body

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    Re: Help Need a workaround for an NLA Overdrive relay

    If you don't think you'll ever need to turn it off, a more permanent mechanical solution would be to just remove the solenoid and replace it with this: https://www.amazon.com/Overdrive-Sol.../dp/B00VET3N50. With that there would be no need for any electrical mods. The transmission would just always shift to OD when the conditions are right. Tim

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    Re: Help Need a workaround for an NLA Overdrive relay

    If you search the Volvo forums you will find the info on the OD problem. Yea I know not our vans but they used the same transmission. Ipd Sells a bypass kit but really it just a basic relay. no need to bypass it. just a relay. you can use a four or a five pole. If It doesnt fit in the correct spot. You can just run jumper wires to plug. Done!

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