68hemi

I bought a 1965 Corvette radio (saving my original) to have converted to the latest version with blue tooth etc. and installed a speaker set up in the rear of the coupe. It works fine until I turn the lights on and then it looses all power, not even a light. I have no idea what is wrong or where to start looking. The radio is wired in using the factory plug. Anybody have any ideas?

Frankie the Fink

Clearly an obscure safety feature, you need to be concentrating on your night driving and not listening to music!

You need to work through the wiring; something is amiss....the headlights are unswitched battery power; the radio's power (if original harness) comes off the switched voltage from the ignition. One shouldn't interfere with the other...

The only thing I can think of is that you have a weak or run-down battery and turning on something with a high-current draw causes demands that makes the accessories inoperative...

babbah

65GGvert

Post a picture, or tell me HOW your radio is wired to the original radio plug. Where is the black wire with the ring on it from the original plug attached now? There are only four wires on that plug, one yellow for 12v, one gray for dial lights, and two black one of which was originally screwed to the Zbar. Let me know how your new radio is wired now. I think you may have the gray wire connected incorrectly and the radio is shutting down due to the unwanted voltage from the dash lights.

68hemi

65GGvert

You'll have to provide the information I asked for if you want to troubleshoot. If you're "taking it in" for repair, then there's no need to try further. You'll find that the plug is wired wrong or the ground is incorrectly connected. If you want to troubleshoot personally, provide some information. The only thing different when you turn on the headlights is 12v is applied directly to the gray wire that lights up the dial in a stock radio. Rotate the dash lights all the way off and see if the radio plays.

68hemi

Frankie the Fink

Call Gary (Gary Tayman) and describe the problem.....other than what 65GGVert suggests the only other thing I can think of is the radio's internal wiring is boogered up. Perhaps the radio light and radio power are somehow conjoined inside the case even though the plug looks fine....

My Tayman converted 63 radio works thus (light dimmer switch to full brightness):

1. Ignition off, lights off, radio off: radio light is off, radio audio is off
2. Ignition off, lights on, radio off: radio light is off, radio audio is off
3. Ignition off, lights on, radio on: radio light is on, radio audio is off
4. Ignition on, lights on, radio off: radio light is off, radio audio is off
5. Ignition on, lights on, radio on: radio light is on, radio audio is on
6. Ignition on, lights off, radio on: radio light is off, radio audio is on

To wit, there IS a relationship between the dash lights and the radio power.... The radio light will NOT come on, regardless of light switch position (e.g. -- calling for dash lights) unless the radio is on...in which case the radio light comes on REGARDLESS of ignition key position (e.g. with the key off the light can be on even if the radio isn't turned on).

I think I got all this right...

DansYellow66

It sounds like this is an upgraded radio with the latest solid stage guts in it. There could be something in the components that shuts it down when voltage falls below a certain pre-determined level. When you turn on the headlights it may be dragging the voltage down below that level causing it to shut down. Who ever builds them may be able to confirm or dispel this. Does the radio come back to life if you turn the lights off or rev the motor up? Possibly your charging voltage is a bit low.

68hemi

Only if you turn the head light off, revving the engine has no effect on it.

68hemi

I just sent Tayman an email so I will see what he has to say.

65GGvert

Have you tried rotating the instrument lights fully off as I asked?

Frankie the Fink

That's the equivalent of #6 in my "truth table" above...my money says the radio stays on....

65GGvert

Except I want the headlights on, dash lights off.

Frankie the Fink

68hemi

Yes, I just tried that and when I have the head lights on and rotate the dash lights off the radio comes back on. When I start to rotate the dash light switch to bring the dash lights back on the radio shuts off again.

Tayman just respond with the below:

Darryl,Never heard of such a problem. Doesn’t sound like the radio itself. Check the voltage going into the radio – I bet it drops as soon as the lights come on, whether the radio is on or not, or even connected. The original connector has three pins – the one closest to the corner of the radio is power to the lamp. It should come on with the dash lights, and brighten and dim accordingly. So you should have 12 volts, or less, when the lights are on. The center pin is ground. The third pin is power to the radio. It should have 12 volts whenever the ignition kay is on, regardless of the lights. With the radio off or disconnected, check those voltages. If you lose 12 volts on the power pin when the lights are on, you need to troubleshoot the lights and that circuit.

Frankie the Fink

65GGvert

I would check to see if the black wire with the ring on it still grounded at the z bar. Then I would pull the dial light bulb for the radio out of the radio case and see if it works then. I personally think the internal radio dial light bulb circuit is wired wrong, if indeed the stock plug was not modified.

68hemi

Well, the original radio did not work all that great (typical of any of them I had) and I honestly don't recall if I had the same problem with it or not as I did not have it in the car that long since I bought it. It took a while to recognize the current problem. Sometimes the radio worked and sometimes not. Then I realize it was the lights that were responsible for the problem.

68hemi

I am passing this thread on to my mechanic as I do little of my own work anymore especially electrical as that was always my weak suite anyway.