Hi all, recently I was told by a friendly motorbiker that my right brake light was out on my 1997 D1. Easy peasy - new bulb -- or so I thought. The bulb looked fine. So I used another bulb and that didn't work either so maybe the socket was bad? Checked that and then discovered that when I turn on the running lights the top lights (where the brake light should be) are lit on both sides. When braking then only the middle rear window brake light reacts, the others stay lit. When I turn off the running lights the left brake lights work ( I used a long stick to depress the brake pedal) except the right still does not (even with changed bulb and socket).

Now we recently had a lot of rain so maybe there is a short as I haven't always noted this, but the "right brake light is out" was reported to me before. I just never noticed that this was a problem with the running lights. So now the big thing is how do I diagnose or check this? Could there be a crossed wire, or something else? I don't know much about it, all but that $ is tight and I am willing to learn (hey why else did I get a rover....) I did check all the fuses and besides the rear light assembly haviing one that is rated at 15 vs 20 all check out. (I did use a rated 20 to see if that changed anything and it didn't, but since its not blown I figure its ok?)

With my black lead on the black wire of the assembly connector, I tested the wires in the good (drivers side) assembly. The reverse light and the brake light which I knew are working both had some voltage on it (10.5-10.8 volts if I recall correctly) but no others. Since this was late I think I need to retest with the various light (running lights, etc) options. But, the passenger side def has about 0.5 volts less on the same light. Not sure what that means.

Brakes pressed - no running lights

Running lights on - no brakes

Running lights on and brake light pressed

Rear passenger side 'assembly' and surgery mess from previous owner

drivers side rear light assembly

Again thanks in advance for any help you can provide.
Thanks for any advice you might have to offer in how to troubleshoot this in advance.

 

I would get the wiring diagram and put things back to original, eliminate what the PO did. What do the turn signals do? How about the white reverse lights?

My amber bumper lights are the turn signals, and the red portions in bumper are running lights. The upper side red lights are dim running lights and bright brake lights.

 

@JohnZo Hey there. Thanks for the reply. Yesterday I checked continuity of the rear assemblies and found that a bulb and a socket of the rear passenger brake light was so melted at some point they didn't make right contact. So I had a spare lying around and that did work (for a short while - more on that). As for undoing what the PO did I would love to and do it proper I just dont know enough yet to do so (besides the wiring diagrams). I also dont see power coming to the lower running lights even on the drivers side. Could it be that there needs to be a 'circle' of covering over both taillights? (nor sure what this is actually called). There is a purple wire that continuously has power (about 11.5V) even when the ignition is off! Seems odd to me.

As for the short while, when I tested it yesterday I has both high and low working but later that evening, I had some flickering in the front cabin light and it seems the running light now was off but the brake light worked when pressen. So 'reverse problem' if you will. Im gonna try to take a look at that later today again hoping that I just have a connector loose or socket not turned properly. How that ties in with the cabin light, however is a mystery to me.

 

Nearly any manual and diagram you will ever need can be found in the google drive linked in my signature. Help yourself.

The upper bulb holders in the body mounted tail lights are known to get overheated and deform, preventing proper contact with the regular tail light and the brake light filaments/contacts. They are super difficult to find.

 

Hey @WaltNYC,

thanks so much for the feedback. That was exactly what it was. The bulb socket at some point gor so hot that it deformed the 'stop' measure and so the metal contacts would push the bulb out just enough to not make contact on one side. Luckily I also still had an extra assembly lying around and two socket (only one of which was OK) to replace it with. There are still a few other electrical problems it seem, but at least I can drive it after sundown w/o getting pulled over. Thanks for the link for the diagrams. I'll take a look and see if I can figure out how I can fix that mess with the hitch 'operation'.