I purchased my '99 XJR knowing the Harmon Kardon stereo system needed tinkering but I'm at a loss now. The on/off switch doesn't work so the only way I could get the stereo to power on was by putting a cassette in the tape player. Now that I initially turned the stereo on, it starts on FM radio and turns off like it should when I pull the key out of the ignition. The only issue I have is that every button on the head unit doesn't work with the exception of the volume knob (thankfully). My steering wheel buttons work as well.

I've gone through the entertainment/radio fuses and replaced them just in case. Does anyone have any suggestions or should I just start looking into a new head unit?

Thanks in advance,

Kyle

 

I would carefully use compressed air to blow out debris from behind the buttons, then use an electrical cleaner to douse it down and then blow compressed air in there again. I know the volume knob is like a rheostat and will have decades of dirt and wear in it.

 

The power knob rheostat is known to go bad. I'd take it to a electrical repair shop and have them look at it, sounds like a cold solder joint or two may be at fault as well. Unless your going third party head unit, you could be buying the same problem in the future. It shouldn't cost too much for a shop to fix. Ask an Indie' shop if they know someone.

 

Thanks for the suggestions and I think I'll start with the compressed air idea. If that doesn't work I might just upgrade straight to an aftermarket single din instead of keeping the stock head unit.

 

Keep in mind you have a trunk mounted amp so unless it’s possible to wire the new head unit into the external amp, you may have to run new speaker wires to each speaker.

 

I used the existing wires to the speakers, but I ran my own to the back to my own amp.

 

I sent my radio from my 1999 X308 to Factory Radio Services and Repair to repair the volume control and also put a small external auxiliary jack which you can hardly see. I now use my iPhone to stream into my factory radio. I think they can now do bluetooth. https://factoryradioservices.com

 

If one likes tinkering, panel is easily taken apart. There you can see the possible fault. But since none of the buttons work except volume, it could be one major fault or small fault in a specific spot.