Jump to content

Headlights and OD Stopped Working

Recommended Posts

I realized today that the headlights in my '63 TR4 stopped working. And the overdrive also stopped working. I'm very new to this car and not familiar with the electrical system. Thinking things through, I did just finish working on two things related to my electrics: 

1.) I just added a battery charger cable/lead to the battery. In doing so, I did touch the wrench to a ground by mistake, creating a spark. 
2.) I relocated my dip switch (up higher) to create a dead pedal spot for my left foot . 

Both fuses appear OK. And reading a few forum entries here on Triumph Experience, I understand the TR4 headlights are not fused.  

So what should I check?? Thanks in advance.


Link to post
Share on other sites


my TR6 lights stop working if one of the leads to the dip switch falls off.  As you moved the dip switch has one of the leads dropped off when you tested it?


check the relay for the od by engaging 2nd, 3rd and 4th in turn with the ignition on but the engine not on, and engaging the od.  You should hear a click as the relay engages. If it does click then the relay and solenoid are ok.

Next check is the oil level in the gb and od (it’s shared).  Third check is that the solenoid operating lever actually is ‘set’ properly. Try steps one and two and report back and we can help with the solenoid lever check.




Link to post
Share on other sites


Tread carefully on this one as you are correct that the headlight supply, or the overdrive relay supply, are not fused. 

A quick flash to ground is a spark but a dead short to ground is heat in the wire etc.

I suspect that the flash to ground and the failure are related. Look carefully at the starter solenoid and ammeter live connections . Disconnect the battery to be on the safe side.

The overdrive solenoid should be fed by the ignition key switched supply but this then switches the direct Unfused supply from the ammeter within the relay.

If this is the case and it has not been previously modified a test meter on the relay terminals should reveal something amiss. Check . W1 is live with ignition on. W2 is ground with ignition off , overdrive selected and in 2 3 or top gear. C1 should be live at all times. C2 should become live with ignition on OD selected and in 23 or top.

If C2 is 12v then the solenoid should click when selected.

If all electrics are ok as covered by Dave we will need to look further.

best of luck









Link to post
Share on other sites

Presumably you are from across the pond judging by the posting time so L/hand drive car. As you have been moving wires around at the dipswitch end then check you have connected everything correctly to the dipswitch and the wires to the overdrive are also located on the top of the gearbox cover so I suspect you may have disturbed them too, they are all located top front of your gearbox cover.


Link to post
Share on other sites

Well, I was finally able to check out the TR4 wiring today.  BTW, the car did start and drive fine, and turn signals were working. Just no headlights and OD.  I removed the dip switch, and found a wire off.  Back on, the headlights now working. Yay!  

Was't able to drive the car though, so not sure about the overdrive yet.  Hopefully later this week, weather allowing.  Would be nice if that fixed the OD too.

Thanks again to all for your feedback!!


Link to post
Share on other sites

Hi Tom, if there is no loud clunk from solenoid try moving gear lever from 4th to 3rd and back about 20 times as if there is debris or thick dried grease under one of the isolator switches this may move it and get things working. 


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.