unexplainable electrical problem {lights}

okay have removed, cleaned, checked, and replaced the 7 pin connectors {both as i have 2}, everything was fine, no corrosion, and a good layer of white contact grease...cable fine...disconnected all the lighting {brake lights/running lights/reverse lights/blinkers} to the rear of the tractor at the 5th wheel,, and still have the same problem...in process of tracing out every wire which should be quite interesting considering a 13 yr old truck haha...

 

ok update #@%*&%$ seriously though, have checked lights no water ot corrosion,,,checked connectors,,,found 1 broken ground fixed it now the brakelights dont work at all, and none of the other lights come on with the brake pedal or trolley valve anymore...every clearance light/running light still coming on with ignition switch....with ignition switch off all light switches turn on/off everything just like they should....turn on ignition switch they all automatically come on and cant be turned off except by turning off ignition,,,,funny thing the headlights and the taillights are on the same curcuit and same switch yet the headlights work like they are supposed to but the taillights work like they want to...the best part, the one that makes it all worthwhile, is that nearly every single wire on the truck is either yellow or white....follow that awhile !!!!.

 

qualitytruck...while your offer of help didnt help with my ''important'' problem that i am dealing with, it did make me get down on my back and really check out the fuse/relay panel...having looked into it many times, including several times in the past couple days, until i laid on my back today i never even noticed the *other* row of relays that is tucked neatly into the top of the panel...and yes, a couple were quite corroded/green, and yes you helped cure a few minor problems i have had since i bought the truck...you are the winner of the electrical guru award for the week !!!!! THANK YOU !!!!!...too bad all the white labels are unreadable.....
so, replaced a leaking brake light switch {man that was fun}, checked out every single fuse/breaker/relay, traced wires all over the place for 9 hours today alone, , and as of this minute i am no closer to locating my problem then i was when i first started...and i have quite a bit of electrical experience , not a novice, in fact i once rewired every single wire in a 76 toyota corolla sr5 after the voltage regulator decided 12 volts was not enough and it melted the insulation off nearly every wire on the car...but this has me staring at the floormats...