How to replace the power head cord - Tristar Vacuums

Seems you may have wired it to send power to the power head but not the motor.

Hi Kathy,
I don't know what model of Tristar vacuum you have but I have a tutorial in the link below that explain how to replace the cord.
http://www.diyvacuumrepair.com/cansiter-vacuums/how-to-replace-a-cord-on-a-tristar-vacuum-cleaner/
hope that helps.

There are four points of connection to get power to the nozzle, any one of which can cause this condition, or an on/off condition. They are the connections in the neck of the machine itself where the hose is inserted in front. The second is underneath the hose handle, where it connects to the two pronged sheath cord. The third is at the lower end of the sheath cord where the power nozzle cord connects. The last is the reset itself. That's what I check first when one of them is brought into my shop, because, believe it or not, most people don't know that there's even a reset there. If the little red button is sticking up push it down firmly but not hard. It's possible to push the bottom right out of the reset unit itself. If the nozzle doesn't activate after pressing the reset, start by disconnecting the power cord that goes to the wands. Check for blackened, enlarged connection openings, or charged, blackened prongs. If no problems found there, continue on up the handle checking each connection point for these conditions. If you find the problem at any of the connection points both parts must be replaced, the male and the female ends. That usually means replacing the cords themselves, as the ends are not available separately. If the power nozzle still refuses to run you or a qualified repair person will need to open it up to check the motor itself to see if it's any good. Once the faulty part,(s) are found and replaced it should start right back up and run normally.

You can get the new cord at your local vac shop or you can take the power nozzle to the shop and have it repaired

Can you take a test reading with a meter from the vac socket or the hose handle. If you have power there test the cord for continuity before the motor. Disconnect the wiring from the switch and bypass directly to the motor.
TIP Most power head cords fail at the stress point where they enter the head, but inspect your cord connections at the vac and hose as well. Please post make and model

Try checking the hose connector cord (short cord from bezel outlet to hose). Also, check the prongs on on extension wands.

http://www.vacsew.com/vacuum-cleaners/kenmore-vacuum-parts.html/

Try here

Remove the bag emptor, then there is one screw ro remove where the cord goes into the side of the vac. Remove that cord cover, pull the cord end out, then replace it with a new cord. Put it back together again. The screw will either be a phillips head or a torx.

Very likely it's the cord at the nozzle neck. These cords flex when you vacuum and they often break internally where the cord goes into the neck. Turn the vacuum on and wiggle the cord at the powerhead and see if the powerhead comes on and off. If this happens, then you will have to replace the cord.
On some of the early models, the receptacle in the hose, where it plugs into the top of the wands, will break away from the plastic pins it sits in, and the receptacle will slide back into the handle, which means that it will not plug into the powerhead connection when you connect the hose. You can check this by looking at the end of the hose and observing if the receptacle is sitting flush with the opening it sits in. If it is pushed back, it will not make a complete connection with the powerhead cord that is sitting at the top of the wands.