On regular speed I can vacuum for a long long time but as soon as I switch it to high suction it shuts down after a few...

If it's only 5 months old, I wouldn't be fooling around trying to fix it. It should be under warranty for a year, even 2 years if bought at costco.

The light will have absolutely no effect on the battery life. Your problem could be a caused by a number of things. 1. If you bought your battery from Amazon, Alibaba, or another mail order place, it could be sub standard. These places have no quality control and it's a good place for Chinese manufacturers to unload their sub standard stuff. 2. The Dyson has a sensor that shuts the device off if there is a problem such as overheating. 3.The filter at the top of your motorhead could be clogged. You may not realize that it is because it is very hard to detect. Soak the filter overnight in water, then in the morning shake it under water vigorously to remove dirt. Then rinse and dry. 3 check your vacuum for clogs. I found one in the motor head which was not visible until I disassembled the head.

Merry Christmas Gillian, There are only two possible reasons you're having this problem. Mechanical, in that the power brushes are broken, or not enough suction. If you can rotate the power brushes easily by hand and as you said there is no hair or other debris clogging the mechanism, then the problem must be lack of suction. The filter at the top of the motor head could be the problem. Take it out and soak it overnight in water. In the morning shake it underwater vigorously. You might be surprised at how dirty the water gets. I used to clean mine regularly by rinsing it under the tap, drying it and replacing it. I found out that is not enough. Good luck

Merry Christmas Sue, Any type of fix be it with a hot glue gun or plastic weld glue will hold for only a very short time. As soon as you put stresses on the box, cracks will reappear. The only way to extend the life of the box is to tape up all the cracks from the outside as well as from the inside with clear packing tape. Make sure you clean the areas to be taped well so the tape will adhere a long time. cheers.