Originally posted by mister_e
You revert PIC voltage PIN... VSS= Ground VDD=5Volt And now your PIC is probably burn!!!!

+ you can't connect two 7805 output together...

1000uF at the output of the regulator is unusefull. Can be good to place them at the input (ignition switch). at the output i suggest 10uF(tantalum or 47uF electrolitic) + 0.1uF ceramic.

I'll also suggest to tie to ground unused input to avoid electric interference from any external car noise(common CMOS handling... also avoid to burn PIC). Be sure of your TRIS define for the unused pins... must be set as input.
Programmednew

please forgive me

Steve is absolutely right, your PIC is most likely dead
and this is good for a 16F84.
There are far better chips at much lower prices available.

As you now have got to get a new one anyway this is
a perfect moment to think about a re-design of your hardware.
(This will reduce the total cost of the circuit dramatically!)

Sorry again, but your initial design wouldn't have worked anyway.
In addition to what Steve already has mentioned,
there should be Pull Down Resistors on RB2,3,4,5,6 and RA4

If you need help with the re-design let us know.

Steve

Yet another case where someone started with 16F84 where life could have been so easy.