120 Overdrive Wiring

[Brian]

Hi
Can anybody help an autoelectrical dimwit with the wiring for an overdrive in an Amazon.
I have fitted a J type overdrive into the car and now need to wire it. I am following the wiring diagram for the 123GT in the Haynes manual. I have in place:

1) the switch on the steering column
2) a light on the dash
3) the gearbox lockout switch
4) solenoid
5) relay

The relay is mounted close to the fusebox and as far as I understand it all cabling from the components are correct as per Haynes and are ready to connect to the relay.

Am I right in thinking that on the relay:

Terminal 87 is the feed from the lockout switch and the solenoid. Also it piggybacks for the feed to the dash light.

Terminal 85 is the fusebox feed.

Terminal 86 is the switch on the dash.

Also can I test to check system without running the car? I should hear the solenoid click in and out?

Any help will be appreciated.

Brian

[mike gilbert]

Are you sure you have the correct relay for the overdrive? I ask as i've checked the overdrive on my 1800S and in my workshop manuals and both have the following relay connections:
31b to selector switch
56a to isolator switch on the gearbox and the light on the dashboard
56 to fuse box.
15 piggyback wire to 56.

It may be different for the Amazon but its the same OD system so I'd doubt it.
Mike

[Brian]

Thanks for taking the time Mike.

The relay is from Brookhouse part No.669102 and is confirmed as the overdrive relay in the CVI catalogue. Although I have a relay on the car already that says 'Overdrive' but runs the reverse light etc it's the old aluminium type but I'll check the terminals on that in the morning. I'll also double check with Brookhouse too.


Many thanks again
Brian

[Brian]

OK

I have sorted this wiring out only the Lockout switch appears to be knackered and is not the easiest thing to replace in situ.

The relay is wired so:

Terminal 85 = to column switch and then earth
Terminal 86 = Power from fusebox ignition terminal
Termainl 87 = 4th gear lock out switch and then solenoid
Terminal 87 = Piggyback to indicator light and then earth

hope this might help for future reference

Thanks
Brian

[mike gilbert]

You can of course run the car without the lockout switch in operation - and have the benefit of overdrive in third gear as well as fourth. Just don't leave it on when you reverse the car or it will fry the O/D.
Mike

[222s]

Originally Posted by mike gilbert

You can of course run the car without the lockout switch in operation - and have the benefit of overdrive in third gear as well as fourth. Just don't leave it on when you reverse the car or it will fry the O/D.
Mike

If there's no lockout, won't the o/d also operate in 1st & 2nd gears?

[amazondean]

It would work in all gears and eventualy burn out!!