Yes, these glow red. In sunlight you might not be able to see it, even if you cup your hands. Try in a darker space. If it sizzles it is good.
Thanks, Phil. I was testing these plugs in the closed garage and was cupping my hand. No red glow at all. I tried putting a drop or so of fuel on the glow element expecting to see a bubbling as I remember from the past. All I got was a faint response. Voltmeter says the new battery is right at 1.5 volts. The Cox plug connector voltage checks OK too. I'm stumped!