Hi everyone, my passenger side (LHS - I live in Australia) dome lamp stopped working so I removed the lens very carefully. Then I looked at the diffuser. It is clipped into the side of the housing and cantilevered.
So the best way to remove it is by using a needle nose plier to pull the locator while unclipping it. Do not under any circumstances pull the round lens bit. This will break.
In the attached photo I have pointed to the part of the diffuser you need to gently pull on.
The problem is basically because of the silly way this has been designed. The power is transmitted to the two bulbs using flat steel rods that are heat staked to the back of the housing. The housing becomes brittle and the heat stakes break. The bulb holders twist into the housing and press against the steel rods. Because the heat stakes break the steel rods become loose so the connection becomes shaky. This seems worse on the LHS. The third image shows this arrangement.
Anyway the solution is to repair the heat stake joints. I firstly used super glue to glue some of the more loose rods to the housing then I poured a tiny bit of baking soda over the holes in the rods, letting the baking soda fall through the holes and forming a little mound about the size of a heat stake. Then I squeezed a drop of super glue onto the baking soda. The baking soda and super glue goes hard immediately and replaces the heat stake. The second image shows one of the repaired heat stakes. I should call them baking soda/superglue stakes.
Doing this fastened the rods securely to the housing.
The second problem relates to the the little flanges on the housing that the bulb holders secure to. These are extremely flimsy and they break. I glued a small piece of paper below the bulb hole in the housing and used the baking soda and super glue to build up the flange. The good news is that that super glue bonds very well to the housing. The fourth image shows the bulb back in place and secure.
Here is a powerpoint I made of it.