Car Stereo Volume Goes Up and Down Erratically

It sounds like you may have a stuck or bad switch. Try checking to see if any of the buttons are jammed. If they all seem fine, you will need to check the switches with a multimeter set to check resistance.

Hello
Will you please send me the exact model number of your JVC Arsenal.

turn it down to 75

speaker voice coils could be overheating as amp is too powerful for them or it could be the same thing except the amp!

blaupunkt doesn't supply parts after ten years on their decks. you can try salvage yards.

The protection modes in these units ****. Most new units have them. What I do is turn down settings on deck and turn up amp as much as possible. Then the protection won't turn on because you won't have to turn it up as high.

Check your Ground Wire inside the Truck and Check the Illumination Wire. I Think on Kenwood the Illumination Wire goes with the Power Wire. If they still will not work, You might want to get a Wiring Harness from Schoche.com Please Rate My Response! Thanks!

Car Radio Battery Constant 12v+ Wire: Blue/Yellow
Car Radio Accessory Switched 12v+ Wire: Gray
Car Radio Ground Wire: Brown
Car Radio Illumination Wire: Green
Car Stereo Dimmer Wire: N/A
Car Stereo Antenna Trigger Wire: N/A
Car Stereo Amp Trigger Wire: N/A
Car Stereo Amplifier Location: N/A
Car Audio Front Speakers Size: 4′
Car Audio Front Speakers Location: Dash
Left Front Speaker Positive Wire (+): Pink
Left Front Speaker Negative Wire (-): Purple
Right Front Speaker Positive Wire (+): Green
Right Front Speaker Negative Wire (-): Blue
Car Audio Rear Speakers Size: 5 1/4′
Car Audio Rear Speakers Location: Side Panels
Left Rear Speaker Positive Wire (+): Black
Left Rear Speaker Negative Wire (-): Yellow
Right Rear Speaker Positive Wire (+): Red
Right Rear Speaker Negative Wire (-): White

Maybe a protection component cutting in.
If you have speakers that are too powerful for the radio it may shut down to protect the amplifier from overdriving the speakers. That produces too much heat in the amp chips/transistors and they either have a overload cut out protection circuit or they burn out.
Even if the speakers are the stock fitted ones the wattage could be bigger than the amp in the radio can handle.
There's probably no way of knowing how powerful the speakers in the truck are but you could try the radio with another set.
Max 50 Watts for that radio. If you don't have the manual for it, it's available here:
http://www.kenwoodusa.com/Support/Car_Entertainment_Owners_Manuals/#_

I had this same exact problem when my last older Kenwood Marine stereo cooked itself while I had it up loud for a few weekends on the lake. (smelled like it had burned inside). I went out and bought a new Kenwood KMR-550u stereo deck. (I do not have an additional amp). I hooked it up to the exact connections where my older Kenwood stereo unit had been hooked up, as I never had a problem with this for the past three years until it failed after smelling of burning elelectrical. I had chalked the problem up to heavy rain we had one day. Every time I turned up the volume, sometimes up to 27 out of 35 possible, or 29, or 32, the stereo would suddenly shut off as if I had turned it off. After a few seconds the stereo would come back on, but unless I was quick enough to turn down the volume it would do it again right away. Of course on a boat, we were beached in a cove and the engine was not running when I encountered this. I searched the internet finding hundreds of similar complaints and several dozen theories of all types, but only a couple that pointed me towards the power (voltage) idea as the problem. I put a volt meter on the positive & negative wires powering the stereo. I watched as I gradually turned up the volume, the voltage on the power wire gradually decreased from 12.5 volts, down into the 11 range, and as it hit 10.9 or 10.8 volts it shut off typically around a volume of 32. The red power wire in my boat that never seemed to have an issue with my old stereo until it fried was determined to actually be inadequate for the power flow for the new Kenwood, and probably was the culprit of my failed older unit. I offer this sound advice: Run a new pair of positive & negative wires directly from the battery (with an appropriate fuse of course (the deck has a 10 amp fuse in it's back so I would use that at the battery) to the stereo. Check the voltage as you turn the volume up into the high 20's and low 30's to ensure you are still getting voltage in the mid to high 11-12 volt range. The stereo is designed to require a minimum of 10.8 volts to operate, and when it drops below that it protects itself and shuts down.