[wing63]

When my dryer heats up, the top gets very hot and the main circuit breaker trips. If I use the dryer with air only (no heat) it runs just fine. I have narrowed it down the the themal cut-off switches or the blower thermostat. Anyone help as to which one would cause the breaker to trip.

[denman]

Here are your parts
Replacement parts for Whirlpool LEQ9508PW0 29"ELECTRIC DRYER | AppliancePartsPros.com

See the attachment for the wiring diagram.

I doubt it is a thermostat because it has not blown a thermal cut-off or fuse.
But you did not say how you diagnosed it as a thermostat.

A more likely cause culprit is the heating coil being grounded.
Check the heating coil.
Unplug the unit and both wires to the coil.
Check it with a meter, should be around 8 to 12 ohms.
Then check from each side of the coil to the case/frame, both should be infinite ohms (open). If not the coil may have sagged or broken and is touching the case. This can cause it to run on high and draw too much current.

It would also be a good idea to check/clean your vent system.
Also check/clean the blower wheel.

If you do not own a meter, I would suggest you purchase a one. You can get a decent digital multimeter for under $20.00. You do not need fancy though it is nice if the leads are a couple feet long.
If it saves ordering one unnecessary part it has paid for itself and you end up owning a useful tool.
Most places will not let you return electrical parts so if you order it, you own it.
A couple things to watch when measuring ohms and continuity
1. Always remove power from the machine otherwise you could blow your meter.
2. Always disconnect at least one side of any device you are checking. This eliminates the possibility of measuring an alternate/parallel circuit path.
3. When checking for closed contacts and continuity use the lowest scale (Usually 200 ohms). Then try higher scales. This scale is 0 to 200 ohms so if the device you are measuring is 300 ohms this scale would show an open circuit which it is not, you are just measuring outside the scale's dynamic range.
4. When you start always short the meter leads together. This will tell you that the meter is working and if there is any 0 offset.

There is a good STICKY at the start of this forum about it's use.