Oven broiler has stopped working, but broiler element seems fine

Question

I have a Whirlpool GJP84802 electric range and oven. Recently I've noticed that the broiler has stopped working. I had replaced the broiler component about a year and a half ago because it looked like the element had been shorted to the body of the oven and had blown the connector up. Anyway, the replacement was working fine until recently.

I checked the resistance of the element and it registers between 20 and 21 ohms, which seems "correct". I checked the voltage at each end of the element and it's 120V when broil is on, but a voltage difference between the two terminals doesn't seem to register -- it's like both sides of the element are hooked up to the same line rather than having a voltage difference between them, or maybe I'm misunderstanding what's going on? I tried measuring the current also and couldn't get a reading. I think I should expect about 6 or 12 amps if it's 120 or 240V through 20 ohms?

The bake functionality seems to work OK, as do all of the range elements on top.

What could explain this kind of behaviour? Could the internal temperature sensor have gone faulty? Something on the control board? As far as I know there's been no particular "trauma" and the broiler element itself is fairly new and visually appears to be in good order.

I'd like to avoid buying a new oven, but I don't have many other ideas to try out since the element seems to be working and line voltage is (sort of) being applied when I turn on broil mode.

Would really appreciate any troubleshooting ideas!

Update: I've included a shot of the control board. One side of the broiler is hooked up to the brown wire (indicated by the orange arrow). It's kind of a weird transformer/relay thing that, when the contacts are connected, has 120V between the two wires. When the contacts are open, the wires are connected. The other half of the broiler is hooked up to the blue wire (indicated by the blue arrow). The relays are indicated by the yellow arrows. I followed the PCB traces and found that the top right relay was connected to the blue wire -- i.e. the other half of the broiler. When I ask to turn the broiler on, there is a voltage difference of 240V between the two wires the relay is intended to connect, so I'm guessing the relay is not working properly as guessed. I will try to replace it!

Final Update: It was the relay! There's one relay for the bake function and one for the broil. The broil relay was the one in the top right of the image with the yellow arrow pointing to it. $5 in parts and a bit of soldering later and the broil function works again. I'm thrilled! Many thanks to Ed Beal for guiding me in the right direction!

Answer 1

You have lost 1 leg of the 240v supply. If you disconnected 1 of the leads there would be 0 or 120 in both places. If both legs of the 240 are switched by a relay one of the contact sets have failed. Or a bad connection. Since bake works I would be tracing the circuit to the control relay. The element shorting may have damaged the relay and now it has failed would be my guess.

If you have access to the board you may find the right one by cycling and finding the relay that clicks , if you can find a schematic the broil relay will probably be labeled. These Relays are usually under ~15.00 and will usually have 6 connections to the pc board 2 for control 2 hot in and 2 hot out, there may be an extra set that is not used but these cost more so it will probably be just 6.

Most of the time they are encased in black or white plastic once you verify that is the problem unsoldering and replacing the relay will make it just like new.