A Model Number may help other help you.

Could be a power problem.

If you loose half the line it can give a no heat condition as the heater requires 240 volts but everything else runs on 120.

Check the power at the plug with a meter, also check it at the terminal strip in the unit.
L1 to L2 = 240 volts
L1 to Neutral and L2 to Neutral = 120 volts

Note that sometimes loose connections can show voltage with no load but will open as soon as a load is applied. So if the volts measure OK with no load, I would check it at the terminal strip with the unit running. Just be careful as 240 is lethal.

Just remembered this so added it
http://www.applianceaid.com/whirlpool-dryers.html
see #40

Here is the tech sheet
https://www.servicematters.com/d...0Sheet%20-%203979705.pdf

It does tell you that the heater relay is bad.

Am not sure if it is the only part that is bad.
They do not provide much info on what they are monitoring if anything, that would hold the heater relay coil power off.

It would be best to check the relay coil resistance to see if that is the cause of the relay not closing.

Also I would swap them back and see if the unit is now back to the original problem. If not, there is a possibility that the relay coil is shorted and this may have now blown the motor relay coil drive electronics.

If this is the case you will need a new board and a new relay.
Note: that you would have needed these before you did the swap, the board was already blown you just confirmed the cause.

It is very common for these Chinese made heater relays to literally blow out causing the pc board to burn out. You probably blew out the pc board if you left the old relay in!

Could it be that BOTH relays are bad? If so, then how would the motor still run normally?
Cannot see both being bad as the motor was running correctly.

I then did a live test with the dryer running in heated dry. The relay connected to the heater circuit showed 0vDC at the coil terminals and ~200vAC.
I assume the 200 was across the relay contacts.

The board is not telling the heater relay to close.

Run the diags in the tech sheet.

Check all the input devices to the board thermistor, dry sensor etc.
Also the START SENSE P1-5 on the board, this tells the board that the motor is running so it is OK to turn the heater on.

If all OK then by the process of elimination I would say the board is toast.

See the attachment for the tech sheet as I do not think the link I included earlier still works.

Here are the parts
Replacement parts for Kenmore 11063942101 | AppliancePartsPros.com

Sears like to keep parts breakdowns in house but if you go to their parts site you can get the breakdowns. The relays are in the control console.

[COLOR="Blue"]Where do I go from here?[/COLOR]

I would check the power to the unit. If you do not have 240 volts everything will run except the heater.
Try flipping the breaker off/on slowly a couple times. Sometimes you can loose half the line without actually tripping the breaker.
Check the voltage at the plug
L1 to L2 should be 240 volts
L1 to Neutral and L2 to Neutral, both should be 120 volts.
If OK
Unplug the unit and check the wires at the terminal strip in the machine to make sure none are loose or burned out
If OK
Check the power at the terminal strip.
Do this with the heater off and on.
[COLOR="Red"]Be careful as 240 volts is lethal !!![/COLOR]
This may be a jod for a pro if you have no electrical experience!!

If the power is good then you will need 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.