Design Defect - Cigarette Lighter Receptacle causing fuse blow
 

I just had to rebuild the rear receptacle, which had been replaced once before under warrantee. Root cause is the construction which includes a small leaf spring plate on the center electrode which is grounding, causing fuses to blow. It contains small tabs intended to keep it in position, but they can melt through the nylon insulation in the connector socket to bridge, and thereby short, to the ground connection plane of the receiver for the lighter.

The lighter exacerbates the problem by having no means to manually pull the lighter out if it gets pushed in, until it releases thermally, which is of course also the source of the melting heat. Audi should know better than to make any electrical appliance using heat this way.

I fixed it by drilling out the rolled rivet which captures the bi-metallic heat release on the ceramic insulator, then removing the center electrode, which is made of brass, and the grounding spring plate. Replace that with a #6 brass flat-head screw to capture the heat release, using a jam nut to capture the assemblage for proper electrical operation.

It is possible to grind or file the extra screw length beyond the jamnut to allow a spade connection, but better to capture a separate wire and make short jumpers with spade ends to plug into the original plug connector. That results in no permanent modification to the car, while solving the fuse-blowing short. The small jumpers are well hidden beneath the facade between the rear seat heater controls, leaving OEM socket appearance and desired functionality.

I suspect all the Audi lighter sockets are similarly constructed, so if you've got a fuse blowing, that's the first place I'd look.<ul><li><a href="http://www.holzerent.com">http://www.holzerent.com</a</li></ul>