Hello Group Experts,   I'm currently working to remove the dashboard in my '97 Ranger so that I can replace the temperature blend door in the heater/AC plenum (some of you may also have experience with the blend door problem). Question: Does anyone know how to disconnect the main wiring harness connector on the driver's side in front of the parking brake? This is the one that goes through the firewall and must have at least 50 wires in it.   Secondly, it appears that I'm also going to have to remove the plenum assembly so that I can install the new temp. blend door that I got off of E-bay. Since it would be very easy, I think, to replace the heater core at the same time, I'm wondering if it would be wise to do so now since the old heater core is already 9+ years old. I don't have any other reason to replace it now as the heater works fine with no leaks. Any thoughts on heater core replacement as a precautionary measure as I don't ever want to go through this again.      Thanks for any information/advice you can provide.   Richard Pittenger Troy, Ohio 

Sounds like a good idea to me, since you are already in there.