Intermittent Head Unit On/Off

[KR.]

I've had an intermittent fault for a couple of years on my Kenwood DNX516DABS. I've learn to live with it but occasionally (yesterday!) I think I need to take a look at it. It switches itself off before powering back up again. I'm pretty sure it's with vibration, going over a bump etc although this isn't set in stone as some bumps do nothing and others power it down. I can drive for a couple of hours and forget about it or it can cut out several times on a short journey. It's much better on motorways - smoother than patched up/potholed local roads? Note it's powering down, not just losing radio or phone connection, but powering down and restarts after about 20-40 seconds with no input required.

I've had the unit out (while powered up) and checked all the wiring behind the unit, I've shaken the unit vigorously and waggled all the wires but it's stayed on so I'm suspecting the fault isn't something loose internally or at the rear wiring. Not being auto electrics savvy the only other place to check was the fuse box under the gear lever but the fuse looks okay and didn't feel slack, although I've replaced it anyway. The head unit is currently working okay but time will tell and as nothing really has changed I'd be surprised if it's resolved.

One thing that has occurred to me on changing the fuse. When I switched it back on again I had to enter the security code. I never have to do that when it powers down itself. Does that mean that when this is happening I'm not actually losing power to the unit but it's just switching itself off? If it was temporarily losing power (loose connection, ground etc) on going over a bump why don't I have to input the security code when it comes back on again?

 

[Jaysea1973]

I know this won't help. But I have exactly the same issue with the same head unit. Does seem to be worse on rough roads, and when using carplay. I have a new head unit coming soon so I will update if this changes anything.

 

[Chippie1]

I also had this issue on my van few years back same head unit again took it all apart thinking loose cables but it wasn’t could be a manufactured fault

 

[Kind of Blue]

Sound to me as though you may have some loose connections. Perahps at some time it has been unplugged and not firmly re-plugged on reconnection or a wire tap scotch link what ever is not doing its job that sort of thing even a loose fuse holder.

 

[GingerWice]

I've had an intermittent fault for a couple of years on my Kenwood DNX516DABS. I've learn to live with it but occasionally (yesterday!) I think I need to take a look at it. It switches itself off before powering back up again. I'm pretty sure it's with vibration, going over a bump etc although this isn't set in stone as some bumps do nothing and others power it down. I can drive for a couple of hours and forget about it or it can cut out several times on a short journey. It's much better on motorways - smoother than patched up/potholed local roads? Note it's powering down, not just losing radio or phone connection, but powering down and restarts after about 20-40 seconds with no input required.

I've had the unit out (while powered up) and checked all the wiring behind the unit, I've shaken the unit vigorously and waggled all the wires but it's stayed on so I'm suspecting the fault isn't something loose internally or at the rear wiring. Not being auto electrics savvy the only other place to check was the fuse box under the gear lever but the fuse looks okay and didn't feel slack, although I've replaced it anyway. The head unit is currently working okay but time will tell and as nothing really has changed I'd be surprised if it's resolved.

One thing that has occurred to me on changing the fuse. When I switched it back on again I had to enter the security code. I never have to do that when it powers down itself. Does that mean that when this is happening I'm not actually losing power to the unit but it's just switching itself off? If it was temporarily losing power (loose connection, ground etc) on going over a bump why don't I have to input the security code when it comes back on again?

I’ve had the same issue for going on three years. EXACTLY the same symptoms. I was told ages ago by a guy at the car stereo shop it was a faulty head unit. Couldn’t be fixed. I then moved to Nz and still haven’t sorted it. It’s much better when not connected via wire to run apple play so I’ve been making do on Bluetooth for now.

Did you resolve this? Did buying a new head unit help? I’m about to treat myself. I guess I’m worried it will be a waste of money if it ends up being a wiring issue.

If you have the time please let me know! Thanks

 

[GingerWice]

I know this won't help. But I have exactly the same issue with the same head unit. Does seem to be worse on rough roads, and when using carplay. I have a new head unit coming soon so I will update if this changes anything.

Hey, did replacing the head unit help? I’m about to do the same.

Bonus question: what did you buy, and would you recommend it?

 

[KR.]

Sorry for missing replies. I've had the head unit out several times and checked the numerous connections at the back and made sure they're all secure. Whether there's a bit of dry solder hidden away who knows. While I've had the head unit removed and with it powered on I've shaken it vigorously so see if it's an internal loose connection but the unit remained powered up and working. I've also put it back and tried to pull and push the mass of wiring down into empty parts of the dash as it's a tight squeeze. I suspected that some parts of the wiring were under stress in this tight space and this was causing the problem.
I've worked out that when it's warm it goes off regularly. Once it starts going off it can go off regularly , bumpy roads don't help. Bumpy roads and heat is worse. If it's feeling good about itself it will remain powered up and working for the 3 hour drive north without once switching off and on again. The next day it will decide to switch off regularly on the drive home. I can't be bothered with expense of changing it along with inevitable harness and reversing camera issues. That being said it can be infuriating at times.

The thing that doesn't make sense is if I disconnect it I then have to input the security code to use the unit. However when it powers down itself I'm not required to do this which suggests it's something different than a momentary break in the power supply.

 

[KR.]

Update on this. Shortly after the last post I had the unit powering down on me again. I hit the top edge of the unit with the heel of my palm (in frustration more than hope). The unit came back on. I've suspected that heat plays a part in this and the cab heating I tend to use is through the two vents each side of the headunit - the dash above the headunit certainly feels warm/hot to touch after a while. I'm not knowledgeable on the routing of the warm air but switched it to footwell. The unit has not gone off in over 3 weeks, which is a record. It's perhaps a coincidence but personally I think heat is playing a part and bumps make it worse.

Could it be that the 20-40 seconds the unit was powering down was enough for the internals to cool down enough for normal operation? I've gone over the same roads with the same bumps and potholes and the unit is staying on and working as it should. It's no hardship for me to use the heating blowers into the footwell so might be worth a try.

The only part of this that doesn't make sense is summer driving, I'll have been driving with no heating on and in fact the A/C will often be switched to cold. I'll experiment when the warmer weather arrives again.