Replacing Nordyne/Intertherm Sequencer

Hi everyone.

I'm new to the forum, and have absolutely no idea what I'm doing when it comes to any sort of home heating. But I've got a problem and a very limited budget, so I'm going to have a go at it.

A short while back my furnace came on and wouldn't turn off. I had to kill the power at the breaker. When I turned the power on, it seemed to work fine for a few days, then wouldn't come on. My brother asked an HVAC guy at the hotel he works at, who said to replace the sequencer.

The model number is FEH-010HA-04

I'm having trouble finding a sequencer that looks like anything that's in the furnace now. I put the model number for the furnace into my search, but none of the results look right. They all look like they're made up of two stacked pieces, and I don't see anything like that in the furnace.

Here's a photo of the inside of the electrical box in the furnace.

Could someone tell me whether I can use the taller double-stacked sequencers I find on Amazon, or does it have to be a single flat thing like I see in the photo above?

(I do most of my own home maintenance, I just don't know anything about home heating.)