electrical connectors

It's not that difficult but does take some time to note the details and pick the right ones for the connector.
If the terminals don't lock in the housing properly, then they will partially or completely back out when the connectors are coupled together. The result is poor or no contact. Sometimes they work for a while, and then show up as intermittant open circuits. I learned this the hard way first on a jeep, but had it on the a-bodies too.