Audio Systems: Noise on Ford radios, AM, ford e350 van, volt power line

Question
Two trucks, two different AM noise problems, FM OK. Both AM,FM,Cassette.

1995 Ford Ranger, AM weak, noisy, computer hash. Does this radio have antenna trimmer? AM could be better even with ignition off.

2000 Ford E350 van, pulsing (no other noise)which varies with truck speed not engine speed. Sounds like it may be speed sensor. Goes away when touching brakes or truck comes to a full stop. Truck has cruise control but not engaged.

Any repair ideas?  Thanks Greg

Answer
Greg,
The 95 Ford ranger may be picking up noise from the engine computer due to faulty grounds at both ends of the antenna. Sometimes running a ground wire from the case of the radio to the metal firewall can help with noise problems. Check to be sure that the ground straps are in good condition from the hood to the fire wall if used. Also tighten all the fender bolts near the antenna. Modern radios do not have antenna trimmers like the olders radios use to have. With the 2000 Ford the noise may be due to the reactive suspension system. Check all the ground straps and connections on the suspension modules for tightness. I have also found that failing or loose anti-lock sending units at the wheels can cause AM radio noise. You can locate what is causing the noise by pulling out the fuses for the ABS and other systems that may be causing the noise and then insert each fuse one at a time until which fuse when replaced causes the noise. When you find what system is causing the noise you may want to try installing a noise filter in the 12 volt power line for that unit to see if the noise stops.

TOM,
T&D ELECTRONICS
tdeser@zoominternet.net