TR6 Overdrive Relay Questions

[Gerry M]

I have have a 1974 TR6. My overdrive does not engage. With car turned on (not started), shifter in 4th, and OD lever on and off there is no click at relay (Solenoid will engage manually). I suspect the relay may be the problem. I ahve attached photos.

Questions:
1. The horn relay is top and OD below right?
2. Any schematics I've seen show only 4 terminal (W1, W2, C1, C2). I have at least 7 terminal (labelled in attachment). What are they all for?
3. I have one loose red/green wire. Any idea what that is for and where it connects?
4. I have one loose brown wire. It was attached to the broken terminal (5). I assume that is an OD wire.
5. Can terminal 5 be reattached/repaired somehow?
6. Can I simply re-attach loose brown wire to terminal 6?
7. If re-attaching brown to terminal 6 does not solve my OD engagement problem what is the replacement relay I will need?

Your answers and any other suggestions on solution to my OD engagement problem are appreciated.

 

[titanic]

Gerry-I think the relay you are looking at is the starter relay. If your car has the J type OD, which would have been correct for a 74, a relay would not have been used. OD relays were only used on A types. If you go to the Advanced Auto Wiring site, you can download the wiring diagram for your specific year of TR6.
There is a wealth on info on the J type OD (including a troubleshooting guide on this site: https://www.buckeyetriumphs.org/technical/technical.htm
Berry

 

[Trevor Triumph]

We used a relay on our spitfires with the J overdrive. I'm not sure it came that way from the factory, but it seemed like a good idea.

T.T.

 

[Gerry M]

With the one broken brown wire terminal I quess I will need a new starter relay. Looks like its a Lucas 22 RA. I haven't been able to source one locally. Other than mail order, are there 22RA equivalents that a local auto supply would carry?

 

[titanic]

I am a bit confused by your situation. Can you verify which OD you have- A or J? If J type, a relay isn't needed (the sol. only draws 1-2 amps). The starter relay 22RA wouldn't affect the OD, unless someone has tried to use it for the OD circuit.
Berry

 

[poolboy]

See this: it's a bunch less expensive too..but as you can see it does not look like the Lucas relay if that's a determining factor
https://www.6-pack.org/j15/index.php/forum/20-electrical/253732-Improvised-Starter-relay#343986

 

[Gerry M]

Berry its me that was mixed up. It is a starter relay not OD.

 

[titanic]

Gerry-The starter relay is kind of puzzling. It was only used on 74-76 cars. You might try a generic relay as suggested by Poolboy or even eliminating it. I have a 22 RA relay, but don't know if it works.
Berry

 

[tdskip]

Gerry - do you know if the overdrive is in fact good. I know you are focused on wiring but curious if you've run the car and know you've got a good unit. Might be worth checking that before diving into rewiring a bunch of things...

 

[Gerry M]

Yes the solenoid can be engaged manually. That's why I'm focusing on electrical.

 

[titanic]

Gerry-Could you confirm which type of OD-J or A? More info on the problem would be helpfull.
From looking at the wiring dia. for a 74,I think the starter relay is used to provide 12 v to the coil when the starter is in use. Otherwise the coil is fed by the ballast resistor wire which reduces the voltage.
Berry