Disable switch for 86 C4 Doug Nash

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Nov 1, 2019 | 06:57 AM

minipete

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Joined: Mar 2018

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From: Sydney Australia

Disable switch for 86 C4 Doug Nash

Hi all

I have had my 86 for a couple of years now and love it but the function of the 4+3 transmission drives me nuts.

As far as I can tell it all works correctly but I would like to add a switch to disable the Overdrive.

Can anyone point me to an instruction on how to connect this?

I know it varies depending on the year, Mine is an early 86 with cast iron heads.

Thanks in advance
Peter

Nov 1, 2019 | 07:42 AM

Kevova

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Joined: Sep 2013

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From: near the thumb in the mitten

It's electric, there is a switch to turn to enable overdrive. Just leave it in leave off.

Nov 1, 2019 | 08:58 AM

minipete

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Joined: Mar 2018

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From: Sydney Australia

Thanks but the 86 has the button on the gearlever and every time you start the car it defaults to On.

I would like it to stay off unless I want it.

I know that it can be disabled by jumpering a switch on the trans or actuating/disabling a relay just not sure which applies to my car.

Peter

Nov 1, 2019 | 09:55 AM

Kevova

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From: near the thumb in the mitten

I would disassemble console. Either add toggle switch to 12v feed to button on shifter or bypass shifter button entirely. Then mount toggle switch out of the way on console.

Last edited by Kevova; Nov 1, 2019 at 09:56 AM.

Nov 2, 2019 | 03:49 AM

jazfe

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Joined: Feb 2009

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From: Vancouver Washington

https://www.corvetteforum.com/articl...rdrive-bypass/

Nov 3, 2019 | 11:10 AM

tequilaboy

Melting Slicks

Joined: Aug 2003

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From: Lakeville MI

Quote:

Originally Posted by minipete

Today this can easily be done via programming making it rather silly to bother with any hardware based solution. The car would also likely benefit from some (ecm) tuning in general, so could kill two birds with one stone with a custom tune.

Nov 7, 2019 | 05:07 AM

minipete

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Joined: Mar 2018

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From: Sydney Australia

Thanks for the responses.

I am in Australia which could make the re-program route tricky.

I will ask the guys on the local forum if there is someone with that knowledge over here.

Failing that I think I can take the instruction jazfe pointed me to and install a bipole switch to enable/disable the factory OD.

I went on a trip last week and it is the one thing on that beautiful car that bugs me.

Peter

Nov 7, 2019 | 10:42 AM

383vett

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From: moraga ca

That was one of the first mods I made on my C4 when I bought it new. It's been decades, so I don't remember exactly how I wired it. If you have a fsm, you can figure it out pretty quickly.