Mark for Model Number 41788042700 I am totally stumped, please help. This Kenmore/Frigidaire dryer (41788042700) had a flakey control board. Replaced with refurbished board from "P S" and still had odd flashing lights and malfunctioning. They accepted a return. Then, replaced with NEW, not refurb, board 137008010 from a different major vendor. Now, dryer will run but not heat in any operational mode but WILL heat when in "Function Test" mode. Can hear heater control relay click on and off during Function Test but not during normal operation. Thermistor measures 51K at 74 deg. F. High limit stat has continuity. Heating element glows bright during Function Test. Panel lights blink appropriately when Contact moisture sensor bars tested normal as per troubleshooting guide during Function Test. Control panel lights flash and track temperature changes during Function Test. Thermistor resistance changes smoothly when Thermistor removed and heated with outside heat source. About 18K ohms at 100 deg. Thermistor is clean with no cracks, burns or loose terminals. NO error codes either during "normal operation" or when placed in "Test Mode". "Cleared" codes just for the heck of it and no heat problem persists. Motor switch must be working since there is head during Function Test. No loose or broken wires. No lint build up in any part of dryer or venting. No funny noises. Somehow, the heater relay is not closing during normal operation even though there does not seem to be any reason why it shouldn't close. So, any help or ideas would be greatly appreciated.
Answer Mark, You will want to do a voltage check at the main control board on the heater relay. Put the unit into a normal drying cycle and check for 120 vac at the NO on the relay. If there is not 120 vac then the control board is bad and would need to be replaced. If there is power then start checking for 120 vac to the element. on the control side and then check for 120 vac on the motor side. When you test these disconnect one wire so you do not get feed through. Then test the wire and then the element. Also check for voltage drop and make sure that the voltage is not dropping below 215vac when the unit is running. Read More... Answered by AppliancePartsPros.com | Thursday, January 23, 2014