I bought new heater motor for a Broan 100hl how do you change it

Try adjusting the fan lower on motor shaft failing that buy another unit and change motor and return broken motor

sounds like fan motor or its capacitor if so equipped is bad so element is overheating do to poor air flow across it,

The switch that you have works like 3 seperate switches. most of these switches will have gold screws
on one side and silver screws on the other side, lets say that the left is gold and the right is silver, and
the switch may also have a green screw for ground. your 12/2 with ground is your main hot, you may
want to mark it with a piece of tape, so you know it's the incoming hot. the ground off your hot will tie,
to the green screw on switch and continue and tie to your vent light which should also have a ground
the white coming off the hot is your neutral, it will go straight to your white or whites on your heater.
the black hot wire at your switch will go to each gold terminal on one side of the switch,there are two
ways you can do this, go to one side and just run a jumper, or put one wire on each gold screw and
tie in to your hot-black wire with a wire nut. now for the switch legs, you will need to run from your, switch
to your heater either another pair of 12/2s or a 12/3, each side of the switch that has one silver screw,
it's easier with a 12/3 normally a 12/3 will have a red,black,white,and ground.
top switch red to red on heater,black to black on light and the white blue on the vent,so from your switch
to the heater you would have to run a12/2 you would not use the black only the white and ground.
remember the white-neutral coming from the switch will be tied to all the whites at the vent,light,heater
except for the 10/3. the 10/3 is used stricktly for the switch legs. good luck!

I have done this before and it is hard. (big time)One time I just got annoyed and bent the washer and got a replacement one at the hardware store. Sometimes the nut will come off if you pull it gently while "unscrewing" it Try a little WD40 on the shaft to help the squirrel cage off. also prying up gently helps. Good luck.

It sounds like the fan blade may be loose on the motor shaft. You can purchase a new motor for this fan online.
Look here: http://www.centralvacuumstores.com/Bath-Vent-Fan/NuTone/Motor-Assembly/S97017705-Motor-Assembly-.php
http://parts.broan-nutone.com/nutone/Shop?actn=quicksearch&searchtype=all&indextype=7&keyword=8663rp&Search.x=0&Search.y=0

You can probably get the part directly from Broan-NuTone http://www.broan.com/display/router.asp?CategoryID=511

Hope this helps you find what you need.

yes, you should be able to find one..they may have changed the cover but the box should be the same... i know home depot and lowes carries some broan products... i fnot go online and search broan exhaust fans and see if you can locate... it may take a little searching but if it is the sueare type still common to find.... good luck to you ..

Clean and lubricate the shaft. Make sure you loosen any set screws in the fan, there may be more than one. A fan puller may be necessary if it is really stuck, but sometimes you can tap on the motor shaft with something that isn't going to distort the end of the shaft. If you mushroom the end of the shaft you will have a very hard time getting it off. You can also call a heating and air supply and they may remove it for you. If you are buying a new motor, the place you buy the motor may do it for you.

The "diode" that your electrician mentioned is actually a one shot thermal fuse.
You can either go to the Nutone website for parts, or remove the thermal fuse, extract the info written on it and buy a replacement. Mine was a 100C 10A thermal fuse. I got mine from DigiKey.

I ran into the same problem, Lowe's carries Broan exhaust vents. They had both a replacement motor for all generations of 678 fans for $18, and they also had the latest generation of the complete unit for $40. I bought the complete unit, which included the fan I needed. Just unbolted it from the new bracket and bolted it to the old one. The new light housing, trim piece, and lens also interchanged. The existing one was old and yellowed, so this made for a huge improvement. All done from in the living space as well.