Radio shuts off when light are turned on

[coconuthorse]

I recently put in an aftermarket radio into my '94 Toyota. The radio works fine, that is, unless I turn on the dash or headlights. I have subs hooked in my car and they still emit the bass from the song that is playing, but my speakers don't output any sound (lyrics and such).
Any help would be great, and thanks in advance!

 

[sofaspud]

Doesn't seem like it would be excessive draw from the electrical system, so my first guess would be wiring error. Are the mids driven by the head unit or from a dedicated amp?

 

[seankane]

Most units have a orange wire(s) for a dimmer check those to see if they are hooked up and shouldn't be.

 

[coconuthorse]

I'll check these things tomorrow after work. Thanks

 

[Brian Oshman]

The dimmer wire is connected as the ground. It will show ground when the lights are off as it picks it up through the light bulbs. Find a proper ground.

 

[speye]

u have the ground wire of the radio on the dimming cct. of the car....

 

[ThyDntWntMusic]

He said the subs still play.... which suggests the ground isn't connected to the illumination circuit.

 

[TheBaronGroog]

Sounds like HU earth is connected to illumination.
Which Toyota-some have separate amps fitted?

 

[FoMoCo]

A quick check to rule out the vehicles electrical system: Measure battery voltage (right at the terminals) with and without headlights.
It'd also be good to do the same at the head unit to help diagnose wiring errors.