California battery issues - workaround

[Stu65]

Hi all,

There have been a number of posts raising concerns about leisure battery/charging issues, including the following:

1. When setting off, the van displays a “Cable connected” warning on the dash, despite the charging cable having clearly been unplugged.
2. The leisure batteries do not charge while driving, even after pressing the “Boost” button.
3. The leisure batteries no longer charge when the van is connected to an electrical hook-up (EHU).

please note, my Cali Ocean supposedly had the fix applied and was fine for a couple of months. My issues started after I plugged the van in at home to ensure the leisure batteries were at 100% before setting off for a long weekend.

My suspicion is that something in the charging/control system has become confused and is effectively reversing the signals it is receiving. If the system thinks the van is still connected to the mains when driving, it prevents charging from the alternator. Conversely, when connected to the EHU, it appears to think the van is unplugged and therefore doesn't initiate charging from the hook-up.

I came across a post from swabes, who had resolved the same issue by removing the 25A fuses from the fuse board above the leisure batteries and from the fuse board under the bonnet, leaving them out for a few minutes and then replacing them.

I tried this myself and, sure enough, it resolved all of my issues:

• The batteries charged from the EHU.
• They charged normally while driving.
• The “Cable connected” error disappeared.
• We had a successful weekend away using the site hook-up with no further errors.
• Everything worked as expected.
• On the journey home, the leisure batteries were back at 100%.

So, whatever is happening, removing the fuses appears to completely reset the relevant charging/control system.

I had the van booked into my dealer for diagnostics, so I contacted them to cancel the appointment as there was nothing left for them to investigate. I did, however, ask if they could provide a fuse diagram, as I'd like to understand exactly which systems are being powered down when these fuses are removed.

Unfortunately, they declined and simply pointed me towards the owner's manual. I may be missing something, but the information in the manual regarding the fuses amounts to little more than a single paragraph and doesn't provide the level of detail I was looking for.

Does anyone have a detailed fuse diagram for the T7 Multivan, particularly identifying the 25A fuses associated with the leisure battery/charging system?

I've searched online, but most of the information I can find relates to the T6.1, rather than the T7 Multivan. I'd really like to understand exactly what I'm powering down when carrying out this reset.

Finally, a big thank you to Swabes for posting the workaround in the first place. Until VW comes up with a proper fix, at least this gives me a way of resetting the system if the problem occurs again — and hopefully it may help others experiencing the same symptoms.

 

[Toneb]

"Does anyone have a detailed fuse diagram for the T7 Multivan"

 

[Chriskend]

Cracking job, my t7 ocean has been perfect but i have been keeping an eye on the above battery faults just in case i get the same issues in the future. Its typical of vw to hold back information that might effect their pockets. Working in IT for the last 30 years and a fare chunk for Microsoft, the first port of call of any diagnostics is to switch it off and on (the so called finger of destiny). Most of the time (if not all) it cures the issue. All new vehicles are now just computers on wheels so why shouldn’t the same apply to them. The wife and i both run tesla’s and they have a hard reset built in. ( used it once or twice) so why shouldn’t others. Well done on posting this fix, it will help a fair few t7 owners out of a jam.

 

[swabes]

Cracking job, my t7 ocean has been perfect but i have been keeping an eye on the above battery faults just in case i get the same issues in the future. Its typical of vw to hold back information that might effect their pockets. Working in IT for the last 30 years and a fare chunk for Microsoft, the first port of call of any diagnostics is to switch it off and on (the so called finger of destiny). Most of the time (if not all) it cures the issue. All new vehicles are now just computers on wheels so why shouldn’t the same apply to them. The wife and i both run tesla’s and they have a hard reset built in. ( used it once or twice) so why shouldn’t others. Well done on posting this fix, it will help a fair few t7 owners out of a jam.

Hahahaha - I worked at Microsoft for 13 years!

 

[swabes]

I found this when I had the probelm as I was curious like yourself. Its for the multivan so doesnt include the campervan specific unit though:
https://fuse-box.info/volkswagen/volkswagen-multivan-t7-2022-2024-fuses-and-relays#google_vignette

 

[Stu65]

"Does anyone have a detailed fuse diagram for the T7 Multivan"

Thanks, I should have finished that sentence with Ocean campervan as I suspect the reset came about pulling the fuses above the leisure batteries, what you have share is still of value

 

[Stu65]

Cracking job, my t7 ocean has been perfect but i have been keeping an eye on the above battery faults just in case i get the same issues in the future. Its typical of vw to hold back information that might effect their pockets. Working in IT for the last 30 years and a fare chunk for Microsoft, the first port of call of any diagnostics is to switch it off and on (the so called finger of destiny). Most of the time (if not all) it cures the issue. All new vehicles are now just computers on wheels so why shouldn’t the same apply to them. The wife and i both run tesla’s and they have a hard reset built in. ( used it once or twice) so why shouldn’t others. Well done on posting this fix, it will help a fair few t7 owners out of a jam.

I have worked in IT for the last 40+ years and like you have a Tesla so , on the odd occasion it needs a kick it can be done, need something similar in the California!

 

[Chriskend]

I have worked in IT for the last 40+ years and like you have a Tesla so , on the odd occasion it needs a kick it can be done, need something similar in the California!

I totally agree, if it wasn’t for forums like this then there would be a lot more head and arse scratching going on.

 

[Chriskend]

I see there is an issue in the childlock fault thread,,,,,, wouldn’t suprise me if there is a very similar fix

 

[Janneman]

Hi all,

There have been a number of posts raising concerns about leisure battery/charging issues, including the following:

1. When setting off, the van displays a “Cable connected” warning on the dash, despite the charging cable having clearly been unplugged.
2. The leisure batteries do not charge while driving, even after pressing the “Boost” button.
3. The leisure batteries no longer charge when the van is connected to an electrical hook-up (EHU).

please note, my Cali Ocean supposedly had the fix applied and was fine for a couple of months. My issues started after I plugged the van in at home to ensure the leisure batteries were at 100% before setting off for a long weekend.

My suspicion is that something in the charging/control system has become confused and is effectively reversing the signals it is receiving. If the system thinks the van is still connected to the mains when driving, it prevents charging from the alternator. Conversely, when connected to the EHU, it appears to think the van is unplugged and therefore doesn't initiate charging from the hook-up.

I came across a post from swabes, who had resolved the same issue by removing the 25A fuses from the fuse board above the leisure batteries and from the fuse board under the bonnet, leaving them out for a few minutes and then replacing them.

I tried this myself and, sure enough, it resolved all of my issues:

• The batteries charged from the EHU.
• They charged normally while driving.
• The “Cable connected” error disappeared.
• We had a successful weekend away using the site hook-up with no further errors.
• Everything worked as expected.
• On the journey home, the leisure batteries were back at 100%.

So, whatever is happening, removing the fuses appears to completely reset the relevant charging/control system.

I had the van booked into my dealer for diagnostics, so I contacted them to cancel the appointment as there was nothing left for them to investigate. I did, however, ask if they could provide a fuse diagram, as I'd like to understand exactly which systems are being powered down when these fuses are removed.

Unfortunately, they declined and simply pointed me towards the owner's manual. I may be missing something, but the information in the manual regarding the fuses amounts to little more than a single paragraph and doesn't provide the level of detail I was looking for.

Does anyone have a detailed fuse diagram for the T7 Multivan, particularly identifying the 25A fuses associated with the leisure battery/charging system?

I've searched online, but most of the information I can find relates to the T6.1, rather than the T7 Multivan. I'd really like to understand exactly what I'm powering down when carrying out this reset.

Finally, a big thank you to Swabes for posting the workaround in the first place. Until VW comes up with a proper fix, at least this gives me a way of resetting the system if the problem occurs again — and hopefully it may help others experiencing the same symptoms.

I wonder if such a 'reset' couldn't also be done by disconnecting the batteries for a few minutes? In that case, you wouldn't have to go searching for the relevant fuses.

 

[WelshGas]

Volkswagen does not print a fixed, definitive fuse layout in the vehicle handbook because layouts vary wildly depending on your exact model generation (T5, T6, T6.1, or T7 New Multivan), engine, and camper specifications (Beach, Coast, or Ocean ).

How to Obtain Your Exact Factory Diagram
If you are dealing with a newer model (like a T6.1 Ocean or T7 Multivan) and troubleshooting complex electrical faults, it is highly recommended to get the factory-exact blueprint:

1. Go to the official Volkswagen erWin Portal.
2. Register a flat-rate account (a 1-hour subscription costs around €7–€10).
3. Enter your vehicle's unique VIN (Vehicle Identification Number).
4. Download the complete, official "Fuses and Relay Locations" PDF, which is tailored exactly to how your specific van left the factory.

 

[Stu65]

I wonder if such a 'reset' couldn't also be done by disconnecting the batteries for a few minutes? In that case, you wouldn't have to go searching for the relevant fuses.

I did look at this initially, unfortunately the vehicle 12v battery is under the passenger seat and by the looks of it you need to remove the seat to get to it...easier to pull the fuses!

 

[Stu65]

Volkswagen does not print a fixed, definitive fuse layout in the vehicle handbook because layouts vary wildly depending on your exact model generation (T5, T6, T6.1, or T7 New Multivan), engine, and camper specifications (Beach, Coast, or Ocean ).

How to Obtain Your Exact Factory Diagram
If you are dealing with a newer model (like a T6.1 Ocean or T7 Multivan) and troubleshooting complex electrical faults, it is highly recommended to get the factory-exact blueprint:

1. Go to the official Volkswagen erWin Portal.
2. Register a flat-rate account (a 1-hour subscription costs around €7–€10).
3. Enter your vehicle's unique VIN (Vehicle Identification Number).
4. Download the complete, official "Fuses and Relay Locations" PDF, which is tailored exactly to how your specific van left the factory.

Many thanks for the recommendation, I will look into that