4+3 In 1988
Thread Starter
Instructor
Joined: Jun 2004
Posts: 177
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From: Little Ferry NJ
4+3 In 1988
I would like to make my overdrive manually operate. I have seen other posts for earlier models, but not the 88. Can someone tell me what wires in the ECM to connect. Thanks
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
You don't have to do anything in the ECM. Just wire the rewire the console switch to the green wire on the overdrive relay. It's on the firewall in front of the fuel pump relay that looks exactly like it.
Melting Slicks
Joined: Aug 2003
Posts: 3,403
Likes: 398
From: Lakeville MI
As long as you don't mind holding down the button continuously when you want O/D, since it is only a momentary switch in the shifter. This is not a practical solution. Another switch could be used, of course.
The ecm can be programmed to do just about anything you want with the O/D easily enough. Why bother with a manual switch?
How do you want the O/D to operate?
The ecm can be programmed to do just about anything you want with the O/D easily enough. Why bother with a manual switch?
How do you want the O/D to operate?
Melting Slicks
Joined: Aug 2003
Posts: 3,403
Likes: 398
From: Lakeville MI
With 87 and 88, you also have another somewhat crude option that will behave like manual control.
Since these cars employ a first gear switch on the transmission case. You can jumper this switch to make the car think its always in first gear.
In this manner the O/D will not activate unless the on/off switch is activated first.
Note: I have not attempted this method, but it should work.
I think somebody used to sell a jumper for this purpose, but it may just be a stock replacment afterall, as there is no item description. Corvette Clinic. Here's a link:
http://www.corvetteclinicinc.com/
Since these cars employ a first gear switch on the transmission case. You can jumper this switch to make the car think its always in first gear.
In this manner the O/D will not activate unless the on/off switch is activated first.
Note: I have not attempted this method, but it should work.
I think somebody used to sell a jumper for this purpose, but it may just be a stock replacment afterall, as there is no item description. Corvette Clinic. Here's a link:
http://www.corvetteclinicinc.com/
Last edited by tequilaboy; Jul 30, 2007 at 01:41 PM.
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Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
I just have the 85 with console switch, but I have a later year shifter at home, I'll take a look at it when I get off work.
If it isn't latching, you'd need to wire in a latching relay, or just put a toggle switch in somewhere.
