Non-LED Compliant Dash Bulbs

I was warned in other f-chat tutorials before doing my LED instrument gauge conversion not to make the alternator warning light an LED because it's designed to complete a circuit and may not properly function with a modern LED. Are there any other bulbs for which this applies? I ask because I just replaced all the bulbs but cannot get the 3 lights at the bottom of the tachometer to illuminate (Brights indicator and Brake Failure/Parking Brake). All the wiring looks good, and all the other gauge lights function correctly. I got the Parking Brake light to come on with a normal incandescent, but nada with the Brights.

 

I read that, too, but I purchased LEDs that work both ways in all the other sockets. I DID try to reverse them; but no luck.

 

So far that DOES appear to be accurate. I thought maybe since incandescent worked one bulb over but LED didn't, maybe there was something funky going on that was affecting that cluster area. But I just put everything back together last night, and I'm going to test the wires when I get home today to see if it's an issue of bulb, wire, or whatever deeper internal wiring sending the signal.

Guess I wanted to make sure that it's okay to use LEDs everywhere else first.

 

Would this be true of ONLY the alternator warning light, or ALL the five warning lights in the dash (fan, choke, seat belts, hazard)?

 

So, bench tested the tach yesterday afternoon, and the bulbs work fine with current applied. This means either that I have a problem elsewhere in the harness wiring, or that all five instruments need to be fully hooked up in order to properly test. Something else weird is that - after all new bulbs were put into the five warning lights, I can only get the hazard light to come on. Again, either all the instruments need to be hooked up at once for proper testing, or I've got a problem elsewhere. Anyone?