I currently drive a Volvo FH500 on a 15 plate. How do I stop the power to cab cutting out after about 2 hours? It stops night heater kicking in and prevents me turning on cab lights in the morning? Only way I’ve found to get power back is turn key to stage 1 when I wake up, turn it back off then turn night heater on.
Should I leave key at stage 1 over night instead? I don’t leave anything plugged in or turned on over night, other than night heater on a timer.
Any help appreciated.
Cheers
Sounds like a battery fault going into economy mode. Have they been checked?
its probably got a battery guard to save a flat battery. i have one on my wagon and if the battery guard cuts the power the only way to re start for any length of time it is to run the engine for a while. id set a timer for the night heater to come on 10 mins before you get up and buy a thicker quilt 
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Alternatively get the batteries replaced. If they are dying enough after a couple of hours, with no drain, to activate the guard then they must be on their last legs surely? Couple of frosty nights and you could be stranded with a non-starter. Cheaper to change them now than later after a call-out.
You need to leave the keys on position one overnight. The power shuts off after a while as it thinks you’ve left the radio or lights on etc. Leaving the keys in means the truck knows you’re in it. The annoying design floor comes from the dashboard remaining lit up like Blackpool illuminations while you try to sleep. Not good if you need total darkness to drift off
No need to replace the batteries or leave the key in position one. You need to bring it to the main dealer and get the overnight mode reprogrammed. There are 3 options, you want the one where the power will not cut out at nights.
It comes standard with the cutout mode programmed unless you specify it. IIRC it is called “living mode” yours is programmed for “parking mode”
Simples.
I find it safest to leave Key In Position 0 (Living) as it should give you 12 hours of living (as standard) which includes night heater unless Start protection kicks in due to low power or bad batteries.
It is possible to have a dealer change this 12 hour limit so could yours have been altered??
Battery weakness on these is a huge problem for tramping on an otherwise very nice motor so keep a set of jump leads handy is my advice.
Hurryup&wait:
I find it safest to leave Key In Position 0 (Living) as it should give you 12 hours of living (as standard) which includes night heater unless Start protection kicks in due to low power or bad batteries.It is possible to have a dealer change this 12 hour limit so could yours have been altered??
Battery weakness on these is a huge problem for tramping on an otherwise very nice motor so keep a set of jump leads handy is my advice.
IIRC standard living is 3 hours, but you can get that reprogrammed.
First thing to have checked are the batteries, its a simple check and takes seconds. If theres a fault with one or both of them the body (cab ecu) will cut power so that it will still start. You shouldnt have to leave the keys in the ignition with the dash lit up as this just gives further drain, albeit not much but still an unnecessary one.
Thanks for the replies peoples. Will have a word with spanner monkeys at yard.
Wondered if there was anything I could alter myself. But you’ve all answered that.
Try reading the manual that comes with the truck to reset the clock just remove key and put it back in
alix776:
Try reading the manual that comes with the truck to reset the clock just remove key and put it back in
Still cuts out after 2, maybe 3 hours.
Got to take it to Volvo, at some point.
Mine’s programed for living. Good for 12 hours before it starts to close down battery power.
If you ever find the key won’t turn, ie when you insert the key there’s no noise and a warning message appears sayings something about steering lock failure then it will be a wee sensor in the steering column. To fix you swing really really hard on the steering wheel, you’re trying to get the steering column to move and that usually sorts it.
It’s been built in by volvo it’s not a fault it’s on the newer models the idea being to save on battery life because the early ones are constantly having to have them replaced I had 3 sets in 2 years the fridge and tachograph will stay on if you just flick the ignition on and of it will be all on again a pain I know but these new volvo are nothing but pains in my opinion
The one I use at work started doing this last night. Battery warnings on the dash this morning…It’s 6 months old FFS!
Got the battery warning first thing when I picked my new truck up from the dealer. 
I love Volvos, but the power consumption is unreal.
We got advised by the dealer to switch the isolator off for 20 mins. Then switch back on, turn ignition on and let the truck do a diagnostic. This turned off the warning and all is good for now!
Any problems like warning lights coming on telephone not connecting thru Bluetooth can be solved by switching isolater of for a couple of minutes if you have no luck with that you can hold the hazard light button in and this will all so isolate the truck if you still have problems then volvo dealer it is.
I don’t bother with the night heater, I Always find the cab gets too hot even when it’s set on low. I just throw an extra cover on the bed.
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