Mk7 no crank, no battery relay

[OfficiallyColin]

Back with another problem on my Mk7 Jumbo 2.2 RWD, twin battery. (my last non start issue was the ignition relay causing the engine to cut off)

Van has been sitting for about a couple of months but I've had a smart charger connected to the batteries in maintenance mode.
So, I hit the key fob to open the doors, the internal lights come on but the locks don't activate. I open the door with the key.
I put the key in the ignition and I get nothing. The relay under the seat doesn't activate and the dash doesn't light up.
The odometer is working and the immobiliser light is flashing normally, no error.
The indicators and lights will turn on but the radio and fans won't.

I plugged the batteries out from the charger for a few days and the voltage didn't drop but I don't have a way to load test them to be sure.

Any ideas on where to start looking and poking at things?

Thanks in advance.

[Altransit]

Just out of interest, how do you charge both batteries with one smart charger

[OfficiallyColin]

Just out of interest, how do you charge both batteries with one smart charger

Every few days I would swap the clips from one battery to the other.
Would that have damaged them?

[Altransit]

Just out of interest, how do you charge both batteries with one smart charger

Every few days I would swap the clips from one battery to the other.
Would that have damaged them?

No, not at all. That's the way I do it, but I wondered if you had a different way.

Your problem is puzzling, unless the front battery is near death Do you have a voltmeter, or a multimeter

[OfficiallyColin]

.

Your problem is puzzling, unless the front battery is near death Do you have a voltmeter, or a multimeter

I have a multimeter. The charger also has a voltage display.
When I first connect the battery it usually reads around 12.5, the charger brings it up to 14 and does its thing.

I left them disconnect from the charger for over a week to see and the voltage didn’t drop.
And I’ve no way to load test them locally that I’m aware of.

Only thing I can think of is my solar & lithium leisure battery in the back. It has a smart combo dc/dc charger solar controller connected to the accessory terminal on the seat. The charger monitors all the voltages and will divert solar power to the van battery if needed and disconnect if not needed. I can only wonder if this messed something up. Lithium house batteries are good and I can monitor them with my phone.

[OfficiallyColin]

As an update, I bit the bullet and bought two new batteries from Halfords.
Same issue. I I disconnected the solar system for the house batteries and tried to bypass the dual battery relay. No change.

[DanMK7uk]

Time for an ignition switch perhaps

[OfficiallyColin]

Time for an ignition switch perhaps

I actually changed the ignition switch about a year or year and a half ago trying to root out a problem. My last non start issue was the ignition relay. I could always put the old ignition switch back in to see since it was never the problem in the first place.
I'll give that a go and update

[DanMK7uk]

Worth a go bud

[Altransit]

Worth a go bud

Not sure it is. Ign switch wouldn't affect the central locking, but I suppose stranger things .............!


Dead connecting relay is a puzzle

[DanMK7uk]

Worth a go bud

Not sure it is. Ign switch wouldn't affect the central locking, but I suppose stranger things .............!


Dead connecting relay is a puzzle

Agree mate, but perhaps the fob is a separate issue.

OP said it was stood for a while, months ! so a slight possibility the fob is low on charge.
(Wont cause a non start) as you know, but the remote locking certainly it could.

Other issues may be ignition switch / bad earth / fuse.

OP yet to also confirm if earth points have been checked, particularly that one behind passenger headlight.

https://m.youtube.com/shorts/3x4TAvZV740

[OfficiallyColin]

Sorry for slow reply. It’s been out on the very long finger.
I went at the van over the weekend and changed the ignition switch but it made no difference.
I checked the battery voltage and it hasn’t dropped over the last couple of weeks so they seem ok.
I tried to bypass the repay by connecting both batteries together with jump leads and still nothing.
I have the mileage on the dash, no immobiliser faults and the front interior lights work when I unlock the doors but the battery relay won’t close and activate the rest of the electronics.

Grounds points are good as it had a lot of welding done last year with the underbody being blasted and repaired.

Any ideas what fuses or relays to try checking?

[DanMK7uk]

Any codes to go off mate ?

[OfficiallyColin]

I have a USB forscan reader that plugs into a laptop but my understanding is that the ignition needs to be turned on.
I only used it the once to turn off automatic door locking when driving so I could be remembering wrong.
I’ll try tomorrow and see what I get.

[OfficiallyColin]

Another very delayed update.

Tore the house asunder but could find my usb OBD2 reader so I ended up ordering a wireless one for my phone. It arrived yesterday.
I plug it in and turn the ignition, little lights turn orange on the reader so it's getting power.

Forscan refused to even see the scanner but iPhone app called Car Scanner can see and connect to it. The app runs through a bunch of checks while lots of lights on the scanner flashing orange and green randomly and keeps retrying but ultimately it won't connect to the ECU.

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