Removing connections from bulkhead!
Here's one:
question on the main harness plug on firewall
The male terminals are removed by squeezing the barb shown here and pushing out
These are M&H reproductions. PED is Packard Electric Division. Yours may be marked differently.
Definately go under the dash and remove the mating female terminal to check for condition. For that flatten a cotter pin or get the terminal removal tool.