ACC vs. RUN keyed

[mjoekingz28]

Ok. I turn my key one slot on a 2003 Chevrolet Silverado and the battery dash light comes on and really nothing else that I notice happens.

But if I turn one more slot to RUN I heard some strange noise from under the hood. What is this noise? Is it fuel pressurizing?

Ok, onto the main part. My wiring harness for my radio has been hacked. They didnt use one to install an aftermarket radio and just cut up the wires. I have to turn my key two notches to the RUN position for the radio to play, unless I am driving of course with the engine on.


So, how can I get my radio to play on ACC and what would benefit from that? If you say it will drain the battery at a slower rate, then please explain why. All I know, is when I want to hear the radio whilst parked, I go into RUN, turn off the auto headlights, make sure it is out of reverse (back-up lights), and turn the gauge cluster down to conserve juice so as not to have a dead battery. So, is my radio installed wrong and after the fuel pump primes, what else is going on with the key in RUN with the engine off?

 

[supton]

In run, it is powering up the fuel pump, and the ECU. It'll drain the battery faster in this mode, as it's all set and ready to run.

Old cars might have the coil powered up also, not sure how much of a load the later distributors were (but before ECU's were the norm).

Odd that your radio won't work in ACC. Is it aftermarket? I'd think even switched +12V would be on in ACC, but apparently not. Personally, if it's an aftermarket radio, I'd start over again the wiring--who knows what they tapped to make it work.

Then you could tap a non-switched +12V (or run to the battery) (don't forget proper fuses!) and be able to turn the radio on with the key removed. If you so wished.

 

[kschachn]

Yes it is installed wrong.

And what runs in that position depends on the car. On my BMW the auxiliary electric coolant pump runs, as well as the electric cooling fan if the A/C is switched on. Probably all the control modules as well, so between all that the battery would drain in a hurry if I left it in the "ON" position just to listen to the radio. I can also hear some of the stepper motors running in the climate control as it presumably tries to control the temperature.

On your truck I'm going to guess that there is electronic circuitry powered up when "ON" that isn't in ACC.

 

[bubbatime]

Your current radio (aftermarket?) is installed incorrectly. Should be pretty easy to remove it, switch the power wire to the proper accessory power wire.

In the run position, your fuel pump is energized, your computer is energized, the coil is energized, the alternator is energized, etc. Basically, you are running your battery down and could be causing damage to some electrical components. I burned up a coil doing that when I was 16 because I didn't know better. I'm not sure if the newer cars have safeguards built in or not to prevent damage to electircal components.

Basically, as your car sits, dont listen to the radio with the engine off until you can get it fixed.

 

[George7941]

If you are hearing a "whoosh" noise when turned to RUN, it is coming from the instrument panel and it is the stepper motors for the various gauges running as the cluster checks for proper operation of the gauges.