Error code "43"?????

Thanks Marty for the info on the sail switch. We experience the same error code 43 problem. Seemed like the sail switch was stuck in the back position and didn't come forward when the fan started. So I bent a metal coat hanger and used it to pull the switch foward to "unstick" it. I tested the oven turning it on and off a few times and made sure that the switch moves forward with the blower fan starting when the oven was on, and moved back when the oven was turned off. Should be obvious, but make sure the blower is not running and the oven is turned off before you stick the wire hanger back there. A pretty quick and easy thing to try before calling the repairman.

I got the error code 43 on my Thermador oven and after much expense I learned it was something I could have fixed myself. First, the concept: there are two cooling fans at the back of the oven that draw air in from around the oven and blow it over the circuit boards that are underneath the burners. You can hear the fans and feel the air coming out the front of the oven above the door when the oven is turned on (not the range top). This protects the circuits from overheating. In front of each blower is a "sail switch", a little switch with a lightweight metal rectangle attached. When the fans are blowing (any time the oven is on), it pushes the sail against the switch, closing it, and notifying the oven that the cooling is taking place. If the switch doesn't close, the oven thinks the fans aren't working. Also, if the switch remains closed after the oven is turned off, then the next time you turn the oven on, it will also give the 43 error code. This is to avoid giving a "false positive" reading in case the sail switch gets stuck in the closed position. So: first visually check the fans and sail switches. Do they close and open when the fans go on and off? They may need to be cleaned a bit to remove grease and gunk. Also, some of the switches are installed at an angle that prevents the switch from opening up again when the fans go off, causing the "fail safe" error. Finally, if a switch is broken, you must replace it. But its an easy job, once you pull the oven out.

Cooling fan error

We have a Thermador PDR304ZS and had the same issue with the range turning off after several seconds and the blinking blue lights (4 3 error code). Marty's and KCW118 fix explanations and photo are awesome. I carefully grabbed the "sail" switches (metal rectangle in front of each fan) and moved them back and forth many times until I could hear the switch click with each movement. I turned on the range and it stayed on! So helpful - thank you! My wife had just called and service tech was ordering parts to come in a few days. Wife is VERY happy. THANK YOU!