[V8] 1990 V8 minor electrical issue on circuit # 14

[chris brown]

Hey guys, been a while since i've posted because car is running well and i have been on the Harley a lot so its been in the garage a lot. 
About 2 weeks ago i started my car in the evening and it was dark so i put on the headlights and fuse # 14 which is a 5 amp fuse blew. I replaced it with a 5 amp and it blew again but only when i put on the headlights.
 I can drive all day and it wont blow but when it gets dark and i put the headlights on it blows
Its a issue because all the cluster and interior counsel lights are on that circuit, as well as a lot of other stuff that is no as important.  So now at night i cant see my speedo or my tach or anything in that area. 
    also, I put a 10 amp fuse in just for giggles and it did the same thing.  (Blow) 
So one of the things on that circuit is shorted out i suppose. 
This is what is on fuse #14.       (5amp) 
License plate light
Glove light
Engine compartment light
Dash panel cluster, and center console (thats the important one)
Rear ash tray assy.

Does anyone have a idea of what to check first? Which part commonly shorts? 
I think its related to the head lamp switch and all the components that receive power when that switch is turned on.  Im saying that because it does not blow until switching the lights on. 
thanks in advance for any help on this issue. 

Chris 1990V8 4.2L