no heat Thermador RED30V electric oven, power at bake element but no heat

[markcm]

I am trying to troubleshoot our thermador RED30v all electric oven. The bake element is not heating, the broil will warm slightly for the pre-heat function but zero heat on the bake.

The bake element tests about 30ohms.

The Red wire from the back of the controller mark BA on the controller has 240 when in bake and there is 240v at the bake element. It seems there is no return path for the circuit. Can someone help me understand this circuit? With the oven off, I did a continuity test from the element to the controller, the red wire is good but I cannot determine where the other side of the bake element goes. Both wires are red at the element. 

Is the return path through one of the two relays? I've heard about these relays failing causing this same no Bake element heat symptom.

I am mostly looking at the BR,BA,L1,COM and neutral pins. The thick black wire on post L1 seems to be power in, the thick red wire on post BA seems to be power out (energized when bake is on) on has continuity to the back element on one side. I cannot find a wire with continuity to the other side of the back element which is confusing me.

Any help on this is much appreciated.

Thank you.

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[markcm]

I still don't fully understand the heating element wiring on this although I had read about the relays having issues so I disassembled the controller and sure enough, found a cold solder joint on the bake relay. I re-flowed it and we have heat in the bake element again.

Here's a picture of the bad solder joint:

[markcm]

For reference, I believe this is the same controller (AKA: Timer) used in the Thermador REF30, RES30 as well as my RED30V

[MrApplianceMatt]

Nice catch! Thank you for updating your repair. 😀

[markcm]

In case anyone comes across this and wonders if this is the problem they too are facing; I own two of these same Thermador ovens and as of today, years after first posting this, I have now repeated this fix about 5 times on these two ovens.

I considered trying to apply a heat sink to the board but figured if it let loose from the board it could cause a short so I will settle for re-flowing the solder once every few years as the oven is still otherwise a great oven. If you are mechanical and have access to some electronics grade flux and a soldering iron, this repair can be performed in an hour or less. The trickiest part is releasing the tabs on the smoked front face of the display; the tabs are large, 3 on the top and bottom of the front face of the display. You have to use a small flat head screwdriver or similar to pry those while also cautiously pulling the front face from the main body of the control unit. Once that is off, you splay the two black plastic retaining clips from the ends of the control unit to remove them, then the control unit is composed of two boards connected by a series of buss wires, you just bend the two boards open to access the back/inner side of the boards that holds the high current relays and you will see the failed solder joints as shown in my previous images.