I fully concur with Rodney, corrosion on inaccessable extensions especially when there is an excessive number of plugs is a very common problem indeed. Some of the rats nests of extensions that folks bring to me complaining of glitchs is shocking even on simple airplane installations.
I have never failed in clearing that kind of problem up just by cleaning up the installation and eliminating excessive wire and plugs. If you don,t know how to solder its time to learn and acquire the appropriate tools to do so.

With the recent avaliability of a number of different P-38 and P-61 ARF's which are an extreme challange in the wiring system because of the placement of the servos, batterys and rx scattered in three different fuselage's if you will. Attempts to use extensions will result in a horrendous mess of plugs and wire. With these types of airplanes the need for a custom soldered harness soon becomes quite evident. I have both a P-61 and a P-38 arf on my bench right now friends have purchased second hand in one case third party. In each case the the orginal assemblers could not deal with the harness except by stacking extrension on extension.

John