Side markers light up but do not blink

I have a 1997 Tacoma 4WD 2.7L. It came from the factory with side markers that blinked, but when I changed the bulbs recently they stopped working except as running lights. Before you ask, yes I am the first owner it definitely came from the factory as I am describing and has never been modded. Drivers side bulb burned out and when I replaced it I immediately noticed it didn't blink anymore, but the passenger side still did. I pulled the good passenger side bulb to test on the drivers side to see if it would flash and horror of horrors I dropped the darn thing and shattered it. When I put a second new bulb in passenger side it too no longer flashes. I replaced the flasher relay just in case it was going out or something, but that didn't help. The only thing I could read on the old bulbs was B7S, which I think indicates it was from the Toyota factory in CA, but no other numbers. All the sources I can find tell me to use 168 as my replacement, but I'm wondering if there was an alternate bulb used on any of them, or if possibly the slight voltage and wattage differences I see between brands could be affecting the behavior? If anyone has any insight into what might be going on here I would love to figure it out.

 

How many wires into the side marker lamp holder?

 

2 wires going into the holder.

 

Follow them to see where they mate to the turn signals or if there's some junction to select from steady (marker) to intermittent (turn) on the marker wiring. I have no info on the circuit on a '97. Only 2003+

 

It runs to a T, one side heads down to the turn signal, the other heads across and does the same thing on the other (passenger) side.

 

I'm not sure what you mean by junction, but it's just wire bundles, no plugins or anything like that.

 

It's 2 circuits, one for parking and another for turn. Since the bulb has only 2 wire, one is juice the other ground, there has to be some "item" before the juice wire that would select between the mentioned circuits for the single filament to be steady or intermittent.

 

I assumed the flasher relay or ecu handled that, but I'm not good with wiring stuff. I do think I saw someone mention it might be handled by the ECU in another thread. Could it be confused by 12v vs 14v, both of which I see in 168 bulbs, and 3 to 5.2 watts also within 168? I don't see anything obvious under there that isn't just wires and I traced everything to the firewall or close to it.