Installed a JVC aftermarket stereo in the F350 I've been working on the last few months. Worked good sounds good. Last weekend I pulled the engine did a refresh and installed a GM style HEI on the 460. After putting the engine back into the truck the radio will not play when the truck is running. It lights up, finds its station and says its in stereo but no volumn. When I click the key back to ACC it works as it should and if I turn the key to ON but not far enough to crank the engine it works but start the engine and nothing. Checked and double checked all the wiring and grounds. Nothing different except the HEI. Even went as far as to start the truck, no sound, get under the hood and unplug the HEI to see if the sound would come back. Noting. I removed the Dura Spark module and plugged into the switched hot to power the HEI. I dont see how that module would have anything to do with the stereo.
Most newer head units have 2 power inputs, one switched, one constant. You need both, or the head unit won't work. I'd look at exactly where you have those connected. You are probably losing the constant feed for some reason. Try hooking those 2 leads up differently. Just try it.:grin:
I looked into that this afternoon. The switched lead is tied into the factory radio power and the constant for the memory is to the cig lighter. I'll try running the switched to a different source as a test. Its like somehow its sensing the charge input when the engine is running. I have no idea what else would be different. Its weird
Called JVC customer service. told em what was going on and turns out theres a patch available for the firmware. have to download a file onto a flash drive and load it into the radio. Freaking weird
