Hi Guys,
My 1992 SC400 has been developing a worsening problem. My AM radio reception has been getting worse and worse by crackling a lot when going through underpasses and losing reception only miles from the city on typically strong stations. It also gets worse when the brake lights or other accessories are on. Use of the turn signal also causes it and other dash lights (ECT and O/D) to fade and strengthen at each blink.

The diagnostics show good alternator, regulator, and battery so the only guess is that I have a grounding problem somewhere. Has anybody gone through this type of problem before and where should I start. All wiring at battery is visibly in very good condition.

Cheers,
James

 

try the amp ground at the back.

 

Thanks for the amp hint. I just finished taking my antenna mast out of the motor assembly and cleaned a very dirty copper base conductor as well as unseized one of the antenna sections. We'll see how the reception is tomorrow as well as the signal light effect on lights and reception. The antenna has a ground to the body with an elaborate little system that has room for failure so with some luck this might sort it out. If not, I'll look at the amp as it does draw a lot of power.

Cheers,
James