Radio/Headlight problem

[Wike]

Installed new sound system a short time ago. Works great until I turn on headlights....Radio turns off. Turn headlights off, radio turns on. Am I lacking power for both or what is the deal. Need help please!! 74' TR6

 

[KVH]

Is your "hot" wire to the radio directly connected to the accessory prong of your ignition switch? Be sure before doing anything that you disconnect the battery, and that you have a fused connection to power in case anything shorts.

Are you sure nothing at the ignition switch is shorted and that you didn't disconnect your headlight wires and put them back incorrectly? I can't recall for certain, but your headlights are probably the thick brown/blue wire, and it sounds like you've got something wrong there. Also, check where you've taken your power from for the radio. Certainly, not directly to your battery.

 

[alanjohnturner]

Does the sound system have a wire connection in the ground side or is it grounded by a connection to the case?

This sounds to me like a fault in the ground return method you have used.

I suspect that the sound system is grounded through the headlights. The ground "goes away" when you turn the lights on.

 

[CJD]

What's a radio?

Seriously, sounds like you grounded the radio to the positive headlight wire behind the dash. It is getting it's ground through the light filaments, but when you turn on the light switch, the radio "sees" 2 positive inputs. The headlights take around 10 amps to light, so the radio uses considerably less juice.

Of course, this may have happened because a common ground is loose somewhere. For example, the screw where the radio is grounded may be the same screw grounding the lights. That screw is not making good contact with the chasis, but the wires are making good contact with each other. So, the lights are grounding through the radio. ..kinda the opposite of the obvious?!?

Still, my first step would be to re-ground the radio to something other than what it is currently grounded to.

 

[CJD]

Yep...ground fault. Bet it fixed itself, but Wike'll be back next time it rains in NY!?!

 

[alanjohnturner]

Hows the chassis CJD

 

[CJD]

Hey Alan! Fraid it's on hold for the spring honey-do's. I should be getting back into it in a couple weeks, though. I'll be sure to post the progress once I do...

Thanks again for the welding tips. They were a big help!