I have the battery tender that the porsche dealer sells. It has worked well for the past two years however now the only light on the display is the power indicator. It does not allow me to select mode.
Does anyone know if there is a fuse in the lighter adapter piece on the charger?

 

Not sure but the Porsche battery maintainer I saw at the dealership last April appeared to be a re-branded CTEK maintainer. Check their web site for the particular model you have, or this site for the manuals: http://smartercharger.com/manuals/

 

Good question. I have a CTEK branded unit and the lighter adapter stopped working. The battery terminals still work, however. The latter is fused. If there is a fuse on the cigarette adaptor it does not appear to be accessible.

 

Not completely familiar with the CTEK but many cigarette adapters do have a fuse - usually accessed by unscrewing the tip of the adaptor.

 

CTEK makes the Porsche charger, it's the multi US 3300. Was advised that the 4.3 also works, it's newer and what I have.

Try emailing or calling ctek for help.

 

On the side of the cig adapter on mine is an 8 amp symbol. It appears that you unscrew the small Phillips screw on the side to access it. I tried to see if plunger at the end was keyed, and it appears to be too small to accommodate the fuze that way.

 

Sure enough. Removing the small side screw allows one to pry open the cigarette adapter and exposes the spring loaded white fuse (below). Tested mine with a continuity tester and it's dead. Thanks for the tip!

 

Good Job. now replace the fuse and it will be good as new