noise from radio

[half]

I have just fitted an LED driving light to my 1995 toyota Corona. it is powered and triggered by a 5 pin relay to shut off when the headlights are on dim, This is to comply with our Road laws. When I energise the light the radio seems to be lower on power and has a hiss I have earthed the radio {Alpine CDA 9825} and the relay and light direct to the battery negative terminal everything is fine when the light is off
Light specs are
Power: 120W
Voltage: 9-32V
LED's: 40x Philips
Color Temperature: 6000K

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[audiobaun 5,000+ posts]

I have just fitted an LED driving light to my 1995 toyota Corona. it is powered and triggered by a 5 pin relay to shut off when the headlights are on dim, This is to comply with our Road laws. When I energise the light the radio seems to be lower on power and has a hiss I have earthed the radio {Alpine CDA 9825} and the relay and light direct to the battery negative terminal everything is fine when the light is off
Light specs are
Power: 120W
Voltage: 9-32V
LED's: 40x Philips
Color Temperature: 6000K

The Relay may need to be 40 amp and on the lights ONLY and the HU on its own source of supply

 

[half]

The way it is wired is the coil is not energised when the light is on the power goes straight from 30 to 87or 87a then to earth. 85 and 86 are the trigger to shut the light off from the dip beam power wire.through the relay coil to earth. it is a 40 amp 5 pin relay

The head unit has nothing to do with the wiring for the light.
All I have done is make the radio earth positive contact with the negative battery terminal to eliminate any earth problems. So everything has a good earth to the battery. I hoped this would stop the noise