Weird tail/brake light behavior - 2004 Grand cherokee (WJ) - help pls

[three_jeeps]

The drivers side tail/stop light is acting strangely. (the passenger side works fine). All references below are regarding the drivers side tail/stop light.

With the lights off, stepping on the brake pedal results in the stop/brake light illuminating. (as one would expect)

Now, turn on the lights (either parking or headlights), and the tail light illuminate. (as one would expect)

Now step on brake pedal, and on the left (drivers side) tail bezel, the tail light goes out, and the stop/brake light does not go on!!

First I inspected the connector and pins on the tail light assembly. Absolutely no corrosion with connector pigtail and socket in bezel assembly. Busses in bezel assembly are continuous-no problem there. Light bulb, bulb holder, and bulb socket are fine. I lightly sanded all contact point, sprayed contact cleaner on plug and socket.

To eliminate the bezel assembly as a problem, , I removed it and checked the voltages on the plug with a volt meter - The voltages at the plug do show the same behavior as when the tail bezel is plugged in....the tail bezel assembly is not the problem....something up stream is acting funny.

I don't understand how stepping on the brake pedal with the lights off causes the brake light to turn on, but when the lights are on, stepping on the brake pedal results in a) no brake light, and b) turns off the tail light. The two circuits should be isolated......


Help pls!!! Any suggestions???? are appreciated!!!!
thanks
J

 

[three_jeeps]

** Update - Fixed**

After checking the voltages at the tail light socket and verifying that they were the correct values at the correct time (e.g when I turned on the lights and/or pressed the brake pedal), I then swapped in the other tail light bezel...everything worked as it should. This told me that something was wrong with the bezel.

Even thought I checked the continuity of the buses in the non-working bezel, and even bent the contacts on the light bulb holders (plugs), it still was not working.
After some head scratching I noticed that the contacts on the inside of the bezel where the bulb 'plug' goes, could be bent up....they were pushed into the plastic too far that when the bulb plug was inserted and rotated, the contacts on the plug did not touch the mating contact in the bezel....bending them up a little solved the problem.

 

[JPNinPA]

Congrats and great explanation. I could visualize it. Pics would be good too but your explanation is easy to follow.

Again great job!