Lighting issues

[Lee96]

Hi,
I had my '67 minor 1000 delivered today, and it will need some recommissioning before going back on the road. Fortunately it seems limited to very simple replacement parts and an electrical issue. I will be doing some more diagnostics over the week but thought I would post here in case anyone sees the symptoms and the cause is obvious.

I find that the sidelights are temperamental, but almost always work if you put the headlights on and then go back to sidelights. If the sidelights haven't come on, the tail lights don't either. I assume this must an issue with the switch?

I cant use indicators with any other lights. If any other lights are on, the indicators simply don't work, neither does the green light on the stalk. I assume this means they don't get enough power, so maybe earthing issues or a poor connection at the flasher unit? I had a 90s motorbike that would do similar things when the battery was knackered and down to about 10 volts.

If the tail lights are on, pressing the brake does not bring the brake light on, it just dims the tail light. Again I assume this means there is insufficient power to the lights/high resistance, so maybe dodgy connections or earths.

The battery leads have slightly wrong clamps on them.

It has a dynamo, and seems to be charging 13.5 volts at idle. If it wasn't for testing, I would just assume it was low voltage.

The plan so far is test the voltage at each light when combinations are used, get some new battery leads with correct clamps, clean up any earth points I can find, clean up any terminals/connections I can find, then test again and see if there is any improvement.

If anyone does have any thoughts or thinks I am missing something obvious please let me know.

[Steve Phillips]

Sounds possibly like you have earth issues,

Check your battery has a good 12v output, although even 10 - 11v is going to be good enough to light everything brightly but without power you’re not going to get anywhere,

I would start by finding all the earth connections make sure that the wire isn’t green as it joins the earth rings or bullet connections as green wire will produce a huge resistance which will stop anything working properly, remove the earth rings and clean the ring and the bodywork where it attaches with something abrasive and re attach using a small amount of copper grease between the ring and the body, same if you have bullet connectors going to the bullet receivers bolted to the body, clean and grease the bullet where it fits the receiver and the receiver as it bolts to the body,

If you have wires with bullet connectors in the light units these will need the same treatment,

And don’t forget the two fuse holder on the bulkhead, the wires to the spade terminals or screws depending need to be clean and tight but also the fuse holder and fuse need to be clean and tight as its pushed into the holder, same with the single fuse in the plastic holder under the two fuse box if your car has that,

Also check the bulbs in the holders I’ve seen bulbs fitted incorrectly, the wrong bulbs fitted, and loose bulbs in holders, all of which give problems,

All of this applies to the live wires as well as the earths by the way, but it does sound a bit like earths,,

Your loom unless it’s been replaced recently will be 55 years old or older so is entitled to need a bit of maintenance,

I suggest you work on one wire at a time, it helps save confusion, and if you have to remove several wires at a single point for some reason take a couple of clear pics with your phone, so you know which wire reconnects to which, as they might not be the same colour to colour,

Check your loom for obvious signs of damage as you go, especially where the loom runs under the car,

DON’T use regular grease between connections as it will insulate and make things worse, copper grease conducts electricity so is correct to use.

Same with your battery put a small amount or copper grease on your terminals, and remember to disconnect the battery if you’re doing anything with the wiring, for testing purposes you don’t need to bolt the terminals back on tight just push them on firmly and your connection will be good enough to check your progress,

You say the battery clams are wrong, possibly they are reversed, so pos on the neg and vice versa, if not a decent local motor factor should be able to supply new clamps or leads,

Minor wiring is fairly simple but old, so patience, work methodically and get a workshop Manuel even a Haynes as it will help show the wiring layout,

Hope some of that helps.

Steve

[Lee96]

Sounds possibly like you have earth issues,

Check your battery has a good 12v output, although even 10 - 11v is going to be good enough to light everything brightly but without power you’re not going to get anywhere,

I would start by finding all the earth connections make sure that the wire isn’t green as it joins the earth rings or bullet connections as green wire will produce a huge resistance which will stop anything working properly, remove the earth rings and clean the ring and the bodywork where it attaches with something abrasive and re attach using a small amount of copper grease between the ring and the body, same if you have bullet connectors going to the bullet receivers bolted to the body, clean and grease the bullet where it fits the receiver and the receiver as it bolts to the body,

If you have wires with bullet connectors in the light units these will need the same treatment,

And don’t forget the two fuse holder on the bulkhead, the wires to the spade terminals or screws depending need to be clean and tight but also the fuse holder and fuse need to be clean and tight as its pushed into the holder, same with the single fuse in the plastic holder under the two fuse box if your car has that,

Also check the bulbs in the holders I’ve seen bulbs fitted incorrectly, the wrong bulbs fitted, and loose bulbs in holders, all of which give problems,

All of this applies to the live wires as well as the earths by the way, but it does sound a bit like earths,,

Your loom unless it’s been replaced recently will be 55 years old or older so is entitled to need a bit of maintenance,

I suggest you work on one wire at a time, it helps save confusion, and if you have to remove several wires at a single point for some reason take a couple of clear pics with your phone, so you know which wire reconnects to which, as they might not be the same colour to colour,

Check your loom for obvious signs of damage as you go, especially where the loom runs under the car,

DON’T use regular grease between connections as it will insulate and make things worse, copper grease conducts electricity so is correct to use.

Same with your battery put a small amount or copper grease on your terminals, and remember to disconnect the battery if you’re doing anything with the wiring, for testing purposes you don’t need to bolt the terminals back on tight just push them on firmly and your connection will be good enough to check your progress,

You say the battery clams are wrong, possibly they are reversed, so pos on the neg and vice versa, if not a decent local motor factor should be able to supply new clamps or leads,

Minor wiring is fairly simple but old, so patience, work methodically and get a workshop Manuel even a Haynes as it will help show the wiring layout,

Hope some of that helps.

Steve

Thank you, I really appreciate the amount of advice you have given me. I have cooper grease but had no idea it could be used on electrical contacts, that would have saved me a lot of headaches when I had my old Honda Deauville. The battery clamps are reversed, luckily I have family who sell car electrical bits for a living so I'm getting 2 new battery leads made up for it anyway, for what its going to cost it would be pointless to keep the ones that are on it.