Help with Graphic Equalizer Wiring, 1994 Volvo 945 Turbo

[walczyk]

I just purchased a volvo graphic Equalizer off eBay and the seller cut off the two smaller connectors for some reason. They were cut off a single black wire and single red wire. I thought the black would be grounded to the radio's case by a spade connector, but I have no idea if that's correct or where the red wire would go. I couldn't find any info about this, any help would be appreciated, thanks

[walczyk]

Here is a pic of the situation