Morris Minor Owners Club

Hello everyone, I am new to the forum as a member but have been using for over a year as a source of reference.
I have a 1965 Morris Minor called CC. She is in great condition but am just tidying up a few things. The interior light didn't have a bulb in it so I put one in. I soon realised why it didn't have a bulb in. It wouldn't turn off. Clearly wired up incorrectly, or so I thought so I took it out and cleaned it up but when I confidently wired it back up it blew the fuse. I am now struggling to work out where the three wires go. The horn works (until the fuse blows) and I have had plenty of sparks so clearly have a feed to the switch.
Help.
The wires are Purple, Black and Brown with a black trace and the car is -ve earth.
Many Thanks[frame][/frame]

Welcome to the forum!

Inside the light are 3 terminals, and the connections are the same for +ve and -ve earth.

On one side of the two bulb contacts there is only a push-in connection - the purple wire is connected to this terminal. This is the fused 'permanently on' supply.

On the other side of the bulb there is also a push-in connection PLUS the switch as well. This side of the bulb has the brown/black wire connected to it. The black wire is connected to the other side of the switch.

Operating the interior switch connects the bulb to 'earth', i.e. the body. The same applies to the door switches that do the same thing.

Hi Richard.
Thanks for such a quick reply. I have taken a photo of the light. Sorry its a bit dark but I didn't home until late. Based on this photo should it be black, brown, purple reading from left to right?

Jason[frame][/frame]

The interior light is on the same fuse as the horn

As indicated above there are 3 wires on the light, power feed (purple) connected to one end of the light, a switched earth (black/brown) from door switches connected to the other end of the light (the door switches connect together on the drivers side) and a permanent earth (black) connected to the switch on the light (so the light can be turned on when the doors are closed)
I had the purple connected to the switch on the light and the switch was on, so when the door was opened there is a direction connect from the power feed to earth and the fuse blows.

Also search for Horn Stopped Working as there is a clearer picture of light, but be aware the connections in the picture are not correct.

You should only have the purple wire on the direct connecton to the light, with the other two wires either side of the switch

Hope this helps

Hi Andy,
Thanks for the reply. I had a look at the photo in the Horn Stopped Working Thread. It sounds like exactly the same problem but I can see where my confusion lies. My interior light is different to the one on the photo. I will try to post a clearer picture tomorrow for you to see.
Thanks again for your help.

I had the problem of the light not turning off, the switch at the door pillar wasnt pushing in far enough to turn off the light, a couple of washers underneath sorted it.

Thanks David,

The door switch seems to be working. Using my test light it seems to be breaking and making the circuit. However I have now taken them out and cleaned them up just to be on the safe side.

As promised I have taken a slightly better picture. So back to the original question, how do I wire this one up? If you number the connections 1 to 3 from left to right, connections 2 and 3 seem to be insulated from the body of the switch, connection 1 connects directly to the body of the switch.

Thanks[frame][/frame]

Hi Brooky,

The body of the light looks like metal, can you confirm and the black around the connections are insulators and assume the light is fitted similar to my Traveller to a wooden batten under the roof lining so the body of light is not earth via fixings. This light is not the same as my traveller or the one indicated in the post above, so follwoing information may not be correct.

Can you also confirm the type of bulb as it looks like a bayonet type fixing and goes in from underneath in your picture
If that is the case then I think the purple wire should be on connection 2. i.e the connection on the bottom of the bulb.
If the bar at bottom of body is the switch for turning light on when in the car, i.e when switch moved it contacts the insulated underside of connection 3. then I think the black earth wire should go on 3 and the black/brown to 1
This would give power to back of bulb and switch earth via metal of body from door switches.
This is my suggestion from what I have understood from your information, hope this is correct

Hi Andy

In response to your last post

The body of the light looks like metal, can you confirm and the black around the connections are insulators. Yes the body seems to be made from aluminium.

Assume the light is fitted similar to my Traveller to a wooden batten under the roof lining so the body of light is not earth via fixings. Yes, the light isnt earthed through through the fixings

Can you also confirm the type of bulb as it looks like a bayonet type fixing and goes in from underneath in your picture. The bulb is a 5W 12V bayonet and yes it fits from underneath of the image. The tip of the bayonet touches the copper strip and the bayonets connect to the body of the switch.

The wiring combination you suggested is what I thought as can be seen from my first photo, ie 1 = Brown, 2= Purple and 3= Black but with no results.

By making the body live (purple in 1) I had lots of sparks and blew the fuse.

I will have to get the bulb test out again but thanks for your reply. It is reassuring I was thinking along the right lines.

Brooky

Brooky,

I have just dug out an interior light, but it is the festoon bulb type, so the connection positions are different. Also very obvious how to connect it, as it has a plastic body and the connection to the body (earth) is made either through the interior and/or door switches. Yours appears to have a permanent connection to 'earth'?

Can you post a picture of the underside of the fitting?

Thank you to everyone for their advice and suggestions. I think I am just about 50% there.
I took a much more logical approach over the weekend using a multimeter. It confirmed I had a live feed, a good earth and both switched earths were working. I then proceeded to soak the whole switch in vinegar overnight to clean it up. It has come a treat. I then wired it up
Purple Live feed in 1 (body of switch)
Brown Switched Earth in 2
Black Permanent Earth in 3

Guess what? The light came on when I opened the doors! However when I flicked the switch across to turn the light on continually I got a spark and blew another fuse. I have noticed the bullet connectors have not been attached correctly have bought some more and will re connect when I have minute.

I am however still not 100% that I am wiring it up correctly.

Just found this on Ebay with the wires still connected.
I was clearly wiring it up incorrectly.[frame][/frame]

I think you need to swop the wires in 1 & 2 to match the picture. I.e the purple goes on the back of the light and Brown to body of fitting. The way you had it would provide full earth from black to the light switch direct to the live feed purple via the light body and blow the fuse.

Check the above using your meter as the purple should be the only connection to one side of the bulb with the Brown (1) to body and black (3) via switch to body. with meter on ohms test you should get connectivity from 1 to 3 when switch is moved to ON and should show disconnection when switch is OFF. At no point with no bulb fitted should you get connectivity from 2 to either 1 or 3

Hope this helps with last step to get light working

Its Working!!!!

Thanks Andy, I wired it up as per your description but only got intermittent function so replaced all the bullet connectors and it now works really well.

What I have noticed is that the plastic cover gets rather warm and is discoloured where the bulb goes. Can you get an LED replacement for this type of bulb? I have seen LED festoon replacements but not this type of bulb (bayonet 5W)

Another fantastic result for the MMOC Club Forum

Thanks Everyone.

Well Done, I have not looked for LED lights so dont know if they are done for small bayonet bulbs

I have an LED in my interior light you can buy them quite cheaply off ebay. It gives a fantastic light inside which means you can actually use it to find things and of course it doesnt get hot or drain your battery

Hi Lee, do they o LED bulbs for the small bayonet type bulb. If so do you have a link?
Thanks