Retriggerable timer relay

Need to find a relay that will give me a single relay closure using the blinker circuit on a transit bus, want to mask the flashing signal just use the initial input. Not sure how to do this or if it's possible....

I didn't understand. Do you want that when a turn signal is activated, another circuit also activates on and keeps "ON" regardless if the turn signal blinks. Correct?

If I'm correct google for 555 Single Shot

Or much easier, find the wiring that goes from the turn signal lever to the flasher module and intercept it.

If you want a steady relay closure while the turn signal is flashing; here is a link to a similar circuit: https://myplace.frontier.com/~wgmumaw/Fuel Pump Drive/Fuel Pump Drive.html