# Car stereo won't work!! **URL:** \ **Category:** Factual Questions\ **Created:** [December 15, 2012, 9:05pm UTC](https://boards.straightdope.com/t/car-stereo-wont-work/644135 "2012-12-15T21:05:49Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Smokinzone](https://avatars.discourse-cdn.com/v4/letter/s/f05b48/32.png) [@Smokinzone](https://boards.straightdope.com/u/Smokinzone)\ **Post date:** [December 15, 2012, 9:05pm UTC](https://boards.straightdope.com/t/car-stereo-wont-work/644135/1 "2012-12-15T21:05:49Z")
I installed a new stereo in my car but forgot to disconnect the ground cable now my stereo won’t come on. What do I do?? ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [December 15, 2012, 9:26pm UTC](https://boards.straightdope.com/t/car-stereo-wont-work/644135/2 "2012-12-15T21:26:52Z")
What ground cable did you not disconnect? The main battery ground? Frankly if this is what you didn’t disconnect don’t sweat it that instruction is a CYA from the guy that wrote the instructions. If you didn’t get sparks wiring it up the failure to disconnect is not your problem Now does the unit light up at all? If no check power and ground to the stereo. Go back through the instructions and verify all the wires are connected correctly. Make sure the power cables have power\* ( one should be hot all the time, another only when the key is on). Make sure your ground is good. If all that is right you might have a dead unit. Happens. If the unit lights up but no sound check the wires from the unit to the speakers. - make sure you didn’t blow a fuse. ---
**Author:** ![bot3](https://avatars.discourse-cdn.com/v4/letter/b/41988e/32.png) [@bot3](https://boards.straightdope.com/u/bot3)\ **Post date:** [December 15, 2012, 9:48pm UTC](https://boards.straightdope.com/t/car-stereo-wont-work/644135/3 "2012-12-15T21:48:42Z")
Look for a blown fuse on the radio. ---
**Author:** ![Smokinzone](https://avatars.discourse-cdn.com/v4/letter/s/f05b48/32.png) [@Smokinzone](https://boards.straightdope.com/u/Smokinzone)\ **Post date:** [December 15, 2012, 10:28pm UTC](https://boards.straightdope.com/t/car-stereo-wont-work/644135/4 "2012-12-15T22:28:31Z")
I’m going to chec the fuse and see what happens. The radio worked right before I changed the harness now it won’t come on at all ---
**Author:** ![Smokinzone](https://avatars.discourse-cdn.com/v4/letter/s/f05b48/32.png) [@Smokinzone](https://boards.straightdope.com/u/Smokinzone)\ **Post date:** [December 15, 2012, 11:27pm UTC](https://boards.straightdope.com/t/car-stereo-wont-work/644135/5 "2012-12-15T23:27:47Z")
> [@bot3](#): > > Look for a blown fuse on the radio. On the radio or the fuse box?? ---
**Author:** ![bot3](https://avatars.discourse-cdn.com/v4/letter/b/41988e/32.png) [@bot3](https://boards.straightdope.com/u/bot3)\ **Post date:** [December 15, 2012, 11:59pm UTC](https://boards.straightdope.com/t/car-stereo-wont-work/644135/6 "2012-12-15T23:59:58Z")
If the car works fine check the radio. But if the radio is on its own circuit then check that fuse too. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [December 16, 2012, 12:08am UTC](https://boards.straightdope.com/t/car-stereo-wont-work/644135/7 "2012-12-16T00:08:00Z")
> [@Smokinzone](#): > > On the radio or the fuse box?? both. if the auto circuit fuse is blown then it won’t work. if the fuse in the radio (or its power cable) is blown then it won’t work. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [December 16, 2012, 12:48am UTC](https://boards.straightdope.com/t/car-stereo-wont-work/644135/8 "2012-12-16T00:48:39Z")
many cars have two fuses for the radio, but only one of them will be labeled “radio.” Older (non-bus-controlled) radios have two “power” wires; one is a “battery” wire which is powered all of the time, and the other is a “key-on” wire which is only powered when the car is in ACC or RUN key position. One of those feeds is usually on a shared circuit, so you’ll probably want to check _all_ the fuses.