Hi! I have a 1980 Volvo 242GT that comes with electronic overdrive. I am curious to know if anyone has experience (or has seen a guide on) upgrading the EOD switch featured on 1975-1980 models to the push button switch on later models.

Thanks for your help!

Justin

 

you'd need the OD relay, a suitable socket for it, the new style shift lever with the button, and wire it all up pretty much the same as a newer car is wired.

on the automatic OD's at least, when the light is lit, the OD solenoid is OFF, when the light is OFF, the OD solenoid is powered.

ok, on the manual OD on a 1980, looks like its ignition key power to fuse 11 to the OD switch to the light, and also to the shift position switch to the solenoid, so when the light is ON *and* the gear selector is in the right gear(s), the OD solenoid is powered.

 

Thanks for the reply Pierce! I'll look into this further. If I have all the correct components would this be a simple project if I only had the wiring diagrams to refer to?

 

well, switching the shift ***** likely won't be that simple.

the rest depends on your electrical fabrication skills.


ya know, I am not sure they EVER used the pushbutton OD toggle on a stickshift car. All the cars I've driven with a lycoming J unit had a switch (primarily classic english sports cars, like our old TR-6, which had the OD on a steering stalk like the turn signals, up was OD on, down was OD off).

 

Hmm, maybe I wasnt clear before. I currently have this style overdrive system:

Shifter **** Overdrive Switch Cover Cap 1975-1980 240 260

The car will take its self out of OD when you shift out of 4th, but if you leave the switch on it will shift back into OD right away. I want to switch it to this style:

Shifter **** Cap 4 Speed M46 with Overdrive 1981-

On this style the car takes its self out of OD when the car is shifted out of 4th gear and also turns off the OD, so when you put it back into 4th it wont engage until you push the button.

I know that I will have to add a relay to get it to work this way, I am just not sure how easy it is to connect everything.

To make the switch I have to add in a relay, I think that on the older model

 

naturally, I'm missing the 1981-1983 greenbooks, so I'm looking in the 1984 now...

ok, its pretty simple. relay module 1259750 has 5 pins.

relay pin 31 (black wire) goes to ground.
relay pin 87 (yellow wires) goes to both the OD indicator light in the dashboard and to the OD solenoid (so THIS solenoid is powered when the light is ON, thats the opposite of the automatic OD's I've tinkered with). other side of the light and the solenoid are both grounded
relay pin 85 (red wire) goes to the gearbox switch (thats the one that says you're in 4th). other side of the switch goes to ground
relay pin 86 (black) goes to one side of the pushbutton.
relay pin 15 (blue) goes to both the other side of the pushbutton and to power from fuse 11.

the button and OD light wires are 0.75mm, the solenoid and gearbox switch wires are 1.5mm, so is the blue wire from the fusebox to the relay.

there's a pair of 2 pin connectors, one on the pushbutton, and one on the solenoid and gear box switch wires.

grr, tried to post a wiring diagram but my photo hosting site is having a bad day. maybe later.

 

ok, here's the wiring diagram for the 1984 M46 overdrive...

 

and here's your original 1980 switch activated OD.

 

This is perfect! Thanks a lot I think I should be able to make this upgrade on my own relatively easily