Multivibrator Circuit Simulation

[tronman]

Hello guys.

I am trying to play with RC circuits here. Originally, I was tring to simulate one of my car relays for the turn signal. For some reason the circuit would not oscillate (the circuit schematics is attached). I then started to play with regular simpler astable multivibrator circuits with two caps and two LEDS to check with the circuit would alternate the current which did not happen. I finally managed to work by charging one cap first and with an additonal switch and letting it go.
I then went back to my blinker and the logic with an addtional switch did not work. Can anyone simulate this? Or have any idea how ?

Thanks

 

[dmk]

Has it connection between base and collector of T2?

 

[tronman]

Yeap. Base and collector of T2 are connected. As I see it, this section of the circuit measures the variation of current running across the Shunt R1 (30m). I am not sure how familliar you are but when you burn a bulb of your blinker the the relay ticks faster. I think this is supposed to change the cap reference voltage on the anode to vary the charging time so it will tick faster after a bulb is burned (the bulbs in this case are represented by R10 and R11 on the bottom left).
I guess i am not understading the initial state of caps and BJT´s and how it starts to work as soon as the switch is turned on. Any light?