Morris Minor Owners Club

My van's front side lights come on (as well as the rear stop lights) when I brake. I just thought it was a harmless Morris idiosyncrasy but, unfortunately, the MOT tester didn't share my opinion. He reckons it's the wrong bulb in the stop lights but is a wrong connection from the brake switch not more likely? From the wiring diagram, the stop lights and the side lights should be on completely different circuits. Just wondering where I should start looking for the problem?

It's either a faulty bulb at the rear where both filaments are touching - or a bulb holder with that defect - or just a bad earth at one of the rear units and the brake light is finding an earth path back through the other lamps. When the brake is applied - are the front lights full brightness - or a bit dim ?? First test then is to remove both rear bulbs and press the brake - do the fronts still come on?

Are the rear brake lights or tail lights or both coming on, are the brake lights coming on when you turn the side lights on?

Is your van a 62 or 63 with combined brake light and indicator and the 8 way relay under the bonnet? If so I would suspect the relay.

Thanks for all the responses. The van's a 70 so probably no relay problem and I changed the bulbs to no effect. The stop lights don't come on when I switch on the side lights (but the side lights come on with the stop lights so I think it may be the bulb holder(s). I'm going to go over it properly at the weekend and hopefully get it sorted before I have to pay another £50 for another MOT test. I'll let you know how I get on...

Bad earth on the brake light circuit.....

Have you tried the test I suggested earlier with BOTH rear bulbs removed?

I tried both bulbs removed, then disconnected each, and then both, of the bulb holders. Still the side lights were coming on with the stop lights. I then started cutting back the interesting insulating tape/wire combo festooned under the chassis and lo! someone had made an uninsulated connection on the stop light wire, taped it side by side to a similarly uninsulated connection to the side light wire, then mummified the whole thing in electrical tape. Two insulated connectors later and we're all set for the MOT re-sit. Many thanks to all for the advice and help!

Good grief...... well found !