How should I further diagnose my clothes dryer problem (no heat, stops mid-cycle)?

Question

I own a 13-year-old electric Frigidaire clothes dryer model LEQ2152HS0 which recently started exhibiting the following symptoms:

1. No heat is produced
2. Cycle stops somewhat randomly after 5-20 minutes
3. All diagnostic lights flash constantly -- i.e. no readable error code

It's otherwise in perfect condition. I regularly clean-out the lint screen including beneath the housing all the way out to the vent on the outside of the house.

I have read that this could be a problem with the circuit breaker, so I have reset the breaker with no change in behavior.

I have also tested the supply and I am getting 120V across both Hot-Neutral poles and 240V between the Hot-Hot poles (I'm in the US). I tested by pulling the plug out slightly from the receptacle, and making contact with the dryer plug's prongs both with and without the dryer running, so I don't believe this is a problem with the electrical connection. (It's been suggested that reading 240V with no load can be misleading, but under load the voltage stays constant.)

Given that no heat is produced at all, I'm guessing that the problem is not the thermal limiter, though that's a relatively cheap part to replace.

It seems to me that I'm down to the choice between replacing the heating element itself, or the control board, both of which are more than a few bucks. Is there a good way to further diagnose without randomly replacing parts until it either works or I give up?

I'm just trying to avoid replacing the dryer if a simple replacement part will get it working again.

I have disassembled this dryer 3 times in the past to replace the rear drum bearing, so I've seen the whole thing and know my way around it, and I'm not afraid of taking it apart again to diagnose (or replace a part for that matter). I have a digital multimeter and I'm willing to rest/borrow/buy some relatively simple diagnostic equipment, but nothing too fancy. :)

Update 2022-05-28

I opened the top of the dryer and I can easily see and reach two small components:

I believe the one with the white label (item #145160) is the "high-limit thermostat" part #33 offered here, since that's the one that's mounted directly to the heating element. (The drum is on the bottom of the image, the real panel of the unit is on the top of the image, and the heating element is behind the cosmetically-rusted protective shielding.) The other component appears to be the "thermal limiter" part #36 offered here.

Neither component shows any resistance across the terminals when connected (that is, my ohmmeter behaves the same whether I connect the probes to the terminals of those components or to each other: jumps up to ~20ohm, then drops to zero).

On the assumption that the "high limit thermostat" should normally be "open", I disconnected it and ran the unit for a few minutes on HIGH heat. No heat was produced so I suspect this component either isn't the problem, or isn't the only problem.

The "thermal limiter" description says that it will stop the motor if the dryer overheats. My motor is running just fine, so I suspect this component is working as expected.

It looks like getting to the heating element will require further disassembly.

Update 2022-05-28 pt 2

I don't think I even need the ohmmeter for this diagnosis:

:)

Answer 1

Following @JACK's recommendation, I disassembled the unit immediately discovered that the heating coil was visibly broken (see the image in the updated question). I didn't even bother testing it, since it was so obviously broken.

Sears sells the dryer heating assembly for about $80, but that includes the heating coil, the protective metal housing and ceramic clips, and – the most expensive part of the whole kit – the high-limit thermostat (which is currently more expensive as a standalone part than as part of the heating assembly package). Sears doesn't seem to sell the coil by itself, and doesn't even have a part number for it.

But I was able to find it on Amazon.com for about $12.

Since I've previously replaced the drum bearing (twice!) and I had already disassembled the entire unit, I took a look at the bearing and it wasn't in super-great shape (metal scarring), so I ended up ordering a package which included the heating coil, drum bearing/shaft/clip/grounding ball and lubricant for about $20. The parts arrived on Monday afternoon; I put it all back together in about 30 minutes and immediately got heat.

I was still worried that the cycle wouldn't complete, since I was getting that error-less-error-code originally.

Since Monday I've done a bunch of loads of wet laundry without any issues, so I think I'm all set.

Thanks to @JACK and @Ed_Beal for their suggestions.