solar1,
it sounds like you're talking about the connectors that connect to the ev100 controller card? They do have release tabs on them, those are the only ones i'm aware of like this. All you do is press the release tab and pull out the connector. Depending on the options the truck has there would be two large plug connector called the 'Z' and 'Y' plugs that has about 14 or 16 terminal ports in it, there may not be wires in all of the ports on it but probably most of them. These are all the inputs from the panel and components. Then off to the side of that there are a couple of smaller plugs that may be 4 or 6 port connectors that are connections to the BDI and the other plug would be optional outputs for 1A and FW circuits. Which ever plug it is you'll need a terminal tool to extract the terminal out of the connector if it needs to be replaced. Don't worry about mixing these plugs up, they are all key'd uniquely to each hole they are plugged into so you cannot plug the wrong one into the wrong hole. If they do not want to just pull right out just wiggle them a bit and they will come out.
Do this one thing first though, unplug these connectors one at a time, get a small set of needle nose pliers and you can use those to reach inside the connector slot on the card and take those flat blade pins and put a slight twist on them, not an extreme amount, but just enough to offset them so when the plug is reinserted it will force the pin and female side of the pin to make better contact. Do this first to see if that is the cause before you try to repair the terminal. This was a known issue with these because the type of pin terminal has a tendency to open up over time when heat gets to it and the connection can get flaky. I've fixed many a truck by just tweaking those pins slightly and the problems went away.
Now if you do find that the wire is broken where it is crimped you might can get by with a solder repair by pulling the wire off the terminal, striping it off some and soldering the wire back to the terminal in the connector. I personally would just remove the wire terminal and install a new one but i have the tools and pins to do it with, you may not ;o).