Full beam only works with side lights on but dont on main beam ? so bulbs must be ok ?

Don't understand your post . Side lamps are usually on with any car before switching to main / full beam ?

sorry not good with cars full beam doesnt work when main beam on but if you turn light switch to side lights you can then flash or hold stick to keep full bem on but as soon as you turn light swiitch to main beam full beam stops

Main beam and full beam are the same , just different name . You have main beam and dipped beam . When on dipped beam on most cars , if you move the stalk either forward or backwards it will change to main beam and usually indicate on panel. Holding the switch activates the main beam or allows you to flash which is normal