Car not cranking after on 1995 Lincoln Town Car

I have change heater core on my Town Car 95. Before there
was no beep from passenger side and car was starting . After I
change heater core. Once car start and after that car is not
even cranking. When I turn key the beep start from passenger
side and light go off from dash board. I reopen dash board and check all connection every thing look good. But sill car
is not get start. I do not why beep coming from passenger
side. Please help

Thank you.

1 answer
Can you find the source of the beep? I would try that, see if the beeping is related to the starting circuit. Then I would fault trace the no-start problem, this should lead you to where the problem lies.