Back light problem

[lisadavee]

Any help please would be appriciated . Where to start lol my brake lights are being a total pain . They work when no other lights are on at the back but as soon as i put side lights on or main lights on the brake lights stay on permanently and when i press the brake pedal the side lights go off and on . Its has a new light switch and it was working fine . Just had to replace some brake pipe at the brake light switch and bled the brakes . Any advice gratefully received. Thanks

[RobThomas]

Brake light and side light wires back to front? Swap them over?

Had a similar-ish problem on a car belonging to a neighbour who had put new bulbs in after one had failed. They'd put in bulbs with just one terminal on the base that bridged the 2 terminals in the socket. Took me ages to suss it out. Duh!

If the car is pre mid-1949 you may have the helmet shaped lenses and the bulb holders in those have 2 types of socket that can allow you to accidentally fit the bulbs the wrong way round so that they shine brightly on sidelights and dim on the brakes. The bulbs on these have pins set at the same height and this was later fixed by having staggered pins for all the later cars. For those anoraks, there is a flat section inside the helmet lamp base with a screw next to it where an engraved plate told you which way up to put the bulb, deleted on later cars.

[alexmcguffie]

Sounds like a broken ground wire in the boot to the rear lights. One light is using the other as a ground path. Wiring in the boot often gets neglected and damp can get in there and corrode it.

Alex

[lisadavee]

Thank you both for your responses both very helpful . Wires were crossed , after that was done 1 back side light wasnt working after trying everything found out the live red wire for the side light was dead snapped somewhere within the wiring loom checked all the loom in the boot and all the way under the car but its hiding somewhere under the braiding so have done a bypass .Once again thank you for your help . Lisa