Yet another blower motor circuit question...

'99 TJ 4.0L

So I repaired my bad blower motor circuit and melted wiring harness using the fire prevention article on JP's site plus ftgiles's advice regarding the relay setup. Remarkably, the resistor was just fine, it was basically the wiring harness that melted. It works awesome now. Thank you everyone!!

My question is, I grounded the relay (from the 30 connector on the relay) to the radio's ground using 12 AWG wire. It's crimped and soldered to the end of the mesh ground wire that attaches to the back of the radio. It works just fine, but I have a new CD player coming in a couple days and I don't want to ruin it. I'm wondering if the circuit was hot enough to merit putting in the relays, will it run hot enough to bother the radio? Or is it just because all that current was running through 16-18 AWG wire? I haven't noticed any terrible sound interference or difference when listening to the radio, but the current radio that's in there is pretty old, and I just might be attributing any static that does exist (real or imagined) to the junk unit anyways. Is this all in my head or should I be finding a new location for the ground?