Turn signals and emergency flashers not working

Good afternoon everyone, I know there are a few posts about this but what I've read hasn't gotten me any closer to solving this issue. I have a 1993 Freightliner fld120 the turn signals and emergency flashers are not working they will light up when I engage them but no flashing. I have replaced the turn signal switch (lever assembly) new flasher relay and circuit breaker checked for power where it should be 12.4 volts at all points.All other lights work as they should. ANY HELP IS GREATLY APPRECIATED THANKS IN ADVANCE...

 

Would also like to add that all lights are LED and the flasher relay is compatible, also I did take the square black cover off relay and moved the arm inside back and forth working it manually and it made no difference. Also I do have the Original wiring diagram that came with the truck and will post it for anyone who may need it.

 

First let me say thank you for your response I'm not sure I understand what you're saying, could you expand on that a little more. Thanks again for your response.

 

I guess what I'm asking is where would the connection be broken at ? The speedometer itself or do they share some of the same wiring?

 

Also someone said it could be in the light bar where the turn signal indicators are

 

Ok I'm going to look for that broken connection , Thanks again for your help.