New designer I light doesn't work

You machine has an electrical disconnection somewhere. Most likely it is in the power cord, but could also be inside the machine itself.

Best to take it for repair unless you can test with a different power cord.

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If a new bulb does not work, then it is most likely something else, perhaps the wiring or a connection. You can probably have your machine serviced to get it fixed, or go purchase a light that you can place close to your machine to light the sewing area. There are lights available with attachment clips and a bendable neck that well let you get the light in the right spot. There are also strings of LED lights available on eBay that you can attach to the upper part of the throat to light the work area. I replaced my regular sewing machine bulb with an LED bulb and was surprised how much better it lights.

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Try replacing the light bulb or rerouting the wire so it won't be affected by the light bulb or the foot pedle. Becarefull though because if you rerout the the wireing in the foot pedle you're taking away the off/on swich so it'll stay on. You may want to open up the foot pedle and see if there is anything loose, not conected or broken. The pedal is used as an on/off swich so it may just be stuck in the off position and not making contact when you press down on it so it won't turn on.
If you can't fined a blulb for it by the way you can disconect the socket where you screw it in and install a new one. Make sure the new one will fit in the same hole though. Then it should be easy finding a bulb for it. PLEASE MAKE SURE THE MACHINE IS DISCONECTED BEFOR YOU DO ANY OF THESE THINGS. Good luck!

What model machine do you have? If it is a Designer 1, then if one lightbulb is out the other will not work either - you need to replace both of them. Sorry, it's a horrid job but there's no way around it. The good news is that they can be sourced very cheaply from an auto spares shop. They are the same bulbs as used in car indicator lights, I believe, and are sold at much less cost than a sewing machine shop will charge. Just be sure to get the correct voltage - take in the bulbs from your machine with you when you go shopping for them.

There is no button to turn on the light. When the machine is turned on, the lights come on. If they are not working it means that one of the bulbs needs replacing. If one bulb blows, neither light works. The bulbs are readily available from auto spare parts shops. See page 110 of your manual for instructions on how to replace the bulb.

Page 110 of the manual, in the Care of your Designer 1 section, gives details on how to do this. Basically you need the special tool that came with the machine. One end (marked Out) is used to remove the bulb, and the other end (marked In) is used to put the new one in. You may need to moisten the Out end a little to aid suction when removing the old bulb. It can be tricky getting the bulb out, but it will come out eventually. Lay the machine down on its side on a towel to give you a better view. You should replace both bulbs while you are at it - if one is broken, neither will work. Bulbs are available cheaply from auto spare parts shops.
If you don't have the special bulb removing tool (like a light grey rubbery barbel, but the "bells" are hollow egg-cup shaped) I am fairly sure you could get one for very little cost from eBay or similar.

It is on page 110 under the Care of your Designer 1 section. You need to use the special tool provided to remove (one end) and insert (other end) the new light bulb. Light bulbs can be easily sourced from the auto spare parts department for very cheap prices. You might need to slightly wet the removing end of the device to help provide suction. It is a tricky operation, but you will be able to do it yourself. You might try laying the machine down on its side on a towel to help you see better. Sometimes the bulbs pop out without bother but other times they just don't seem to want to come out - persevere, they will come out in the end. You should change both bulbs at the same time - if one is out, the other won't work. There is one above/beside the needle and the other is in the harp of the machine.

There are two lights on the machine, 1 over the needle and one in the center of the arm. If either light is bad the other will not work so make sure you have 2 good bulbs.

when one faulty, both do not work. replace faulty one & both will then work.