Radio static in old Suburban
I have a 1995 suburban with 58,000 miles. It was my dads and he didn't drive that much and I ended up with it. It's a great tow vehicle but there is one issue. The radio has excessive static. The static rises and falls with engine acceleration leading me to believe it's in the ignition system. The odd thing is, when the static gets real bad I can't turn on the headlights and the static instantly diminishes. If I turn off the headlights immediately after the static goes away it stays diminished for a while. Eventually the static builds back up and once again turning the headlights on will diminish it. This doesn't always work, but turning the headlights on, for whatever reason does diminish the static. The plug wires were replaced about five years ago because of age not because of mileage, but I don't know the quality of the wires since my dad have them replaced. I'm wondering if it may be something else like a voltage regulator, or coil. Any input would be greatly appreciated, thank you.
Does the Suburban have the antenna in the rear window on the glass along with a defogger grid? Or does it have a real antenna sticking out of the fender. Check the ground on the real antenna. But if it has the rear window antenna leads, I'd check the separator box for the antenna lead and the power cable to the rear grid.
Try turning the rear grid on while you're getting static to see if that changes the reception. Inside those separator boxes the connections can corrode from heat of the defogger grid and somehow it affects the connection for the antenna.
I'd also check the grounds for the battery to the fender and any other ground straps from the engine to the firewall, e.g.. Clean each one.
2014 Malibu 2LT, 2015 Cruze 2LT,
The 'Burb has a regular antenna. Like I say, the 'Burb is almost 20 years old. It's been garage kept but does have some corrosion in and on it so it could be the grounds. I suppose the noise could be some kind of component that is going bad in the radio as well. The radio is also susceptible to powerlines etc much more than regular car radios. Basically for everywhere I drive with my regular vehicles the radio gets clear reception. The 'Burb's radio seems to have a limit of about 30 miles AM before the reception gets to be total garbage. I've had this before in older cars, but what is odd is having the lights coming on clearing up the reception. I've never seen that before. Thank you for the input, I will look at the grounds tomorrow.
I'd figure out how to reseat the base of the antenna to the fender to ensure a good ground connection there. Loosen and reestablish a good tight contact.
I'd still suspect the ground leads to the fender from the terminal on the battery. The headlights probably ground to the support grid of metal at the front of the car and use the same ground on the fender. How turning the lights on would make the antenna better able to pick up the electromagnetic signal out of the air is something I can't explain. But if the lights are a factor, I'd consider that they make ground through a poor connection and cause it be better for a time which makes the radio reception work better.
2014 Malibu 2LT, 2015 Cruze 2LT,