Hi all. I'm having a weird problem. The radio in my 07 Prius gets louder by itself. I crank it to 25, and can watch it go up and up. It doesn't always happen, but all of a sudden I'll find it's very loud and check the setting and it's u past 30. Any ideas and help would be appreciated. Thanks, Dom
Do your steering wheel buttons work correctly? If not then maybe they or cable going to them is faulty.
Could be a defective unit. Could be the default source for all sorts of electrical weirdness, a weak 12V battery. Is your "radio" a JBL 6 or 9 speaker premium sound system? You might have a setting for dynamic sound level (DSL) on the MFD that you can turn on or off. If you turn it off does it still act up?
Try to use steering wheel buttons that are on the same side as volume while the volume is changing by itself. For example adjust temperature up. If temperature changes while volume is changing then it has to be with the stereo unit itself. If it doesn’t then it has to be the steering wheel switches or wiring to them.
I'm pretty sure it's not the premium system. Didn't have the money to go with the better model. I'll check the battery. Since it's original, it might be weak. I don't think I have it set for DSL since it doesn't get louder and softer as I accelerate or slow down. And, it does it with no rhyme or reason. I usually notice it when I'm going at a constant speed. Thank you !
I will check that today. I don't think the temp changes when the volume does, but I'll check to be sure. Sometimes, even when I hit the lowering button on the steering wheel, it gets lower and then gets louder again. It might be the wiring, but, it's usually when I'm going straight on the highway at a, sort of, constant speed. Thank you !
I meant that if you can change the temperature while volume is changing it has to be the stereo unit itself.
Got it. I will check that the next time it happens. Hopefully I will remember. lol It doesn't happen regularly so it may take some time. Thank you !
Could be the clockspring inside the steering column as others are diagnosing. If so, you should be able to cause a volume change, and a cooresponding volume indication at the top of the MFD screen, by having the radio on and just slowly turning the steering wheel while sitting stationary. Usually when the clockspring goes it affects the buttons on the right side of the steering wheel first. The recirculate/vent and front/rear defrost buttons.
Never noticed it when turning, only on the highway. I will try that this afternoon though. Thank you !
Good morning. Tried turning the wheel when sitting still. No change in volume and no change on the MFD screen. I'm starting to like the ghost theory. (see above) lol Thanks, Dom
Thought about this on the way to work and back. If it is a break in the clock spring conductor inside the steering column that is affecting the signal path for the steering wheel radio volume control, these signal busses probably use digital signals or at very least resistance values to tell the ECM what to do. The chances of intermittent contacts or grounding out coming up with the value to make the radio volume increase, and doing that over and over as the volume increases, are very small indeed. I think something has come loose inside the radio itself or perhaps a bad connection to the radio unit could be found. You might want to remove the radio case and unseat/reseat all the connectors.
