I am getting a static sound when my key is turned on, car does not need to be
running. It is loud and disturbing. It is there when radio, heat, a/c, and fan are
off or on. Any ideas?
Look for bad grounds in both radio supply and the amps power and grounds, if those check good then you could have either the radio going or the amp and in rare cases both due to alternator voltage problems.
I happened to discover that if I turned temperature up to 85 degrees that static stopped. When I turned it back down, it came back. Go figure . If I went slow the static would not come back on till I hit 73 degrees. This will work till I have a chance to dig into it more.
I have heard of A/C compressors setting up a static field but usually the supressors in the radio stopped them, you might try putting on some supressors on the A/C compressor feed wires, if you can't find any supressors large enough you could try zenier diodes with a rating of around 50 amps.
I just had another thought on this, the temperature blend door is servo driven, it could be a servo motor that is causing the static, but I would have this verified with a lab scope before tearing into the HVAC system, if this is the case it would be easier to put supressors on the radio circuits. HTH
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