R32 MK5 - No dash display after changing battery, cuts out.

[JRC1]

Replaced old battery for a brand new fully charged one yesterday.

All interior lights, headlights etc working fine when new battery was connected. Put the key in the ignitiion after and nothing on the dash after the first turn, no guages like fuel etc working. Radio asking for a code.

Turn again to try to start the car and it immediately cuts out after starting.

Did some research last night and some were suggesting car could be immobilised and to remove terminals from battery, then connect again after some time. Did this but same results.

Any ideas? Recovery chap's thoughts were the fuse for the dash has possibly gone at the point of new battery being connected, and that the car won't maintain a start because the dash isn't working. Does this sound plausible? If so, any idea what fuse needs changing or what else this could be?

Thanks

[Belle427]

I cant help with fuse numbers sorry but id start by checking them, there may be one for the cluster in the engine bay fusebox.
If they all check out id disconnect the battery and leave it for a little longer before reconnecting.

[si_xsi]

I had something similar after one of mine went in for some engine work and they disconnected the battery for a while. When it was eventually all put back together, all the interior lights would work but when you went to turn the key it just started beeping and the dash lit up like a Christmas tree and failed to start, but would turn over.

It turned out to be one of the main relays but the garage had to look over some wiring diagrams to work out which one.

[JRC1]

Thanks both. Left battery off overnight, reconnected - still nothing on the cluster/dash when turning ignition.

Checked every fuse both in the engine bay and the compartment in the cabin next to the steering wheel. 20 amp fuse in position 36 in the cabin had blown, bingo I thought - but when swapping this out for another working 20amp fuse from a different position, still nothing on the dash. Should a working 20amp from another position have sorted it, or do all need to be working?

I really hope it's not a complex relay/wiring issue just from changing a bloody battery!

[si_xsi]

I wouldn't of thought replacing a single 20A fuse will either cure or hinder the issues you describe, I think fuse 36 in cabin is for headlight washers.

Presumably the simple things have been checked, e.g the correct battery type for the car, I'm no expert but am aware some need coding to the car these days. Is anything draining the battery when its connected or is it holding charge OK?

Might be worth getting a trusted mobile auto electrician to take a look.

Be keen to know what it is when you find out!

[BlindedByTheLights]

Tried this?

https://youtu.be/3qAZHIwIUDY?si=hK9IcgOKYq302qub

[JRC1]

si_xsi said:

I wouldn't of thought replacing a single 20A fuse will either cure or hinder the issues you describe, I think fuse 36 in cabin is for headlight washers.

Presumably the simple things have been checked, e.g the correct battery type for the car, I'm no expert but am aware some need coding to the car these days. Is anything draining the battery when its connected or is it holding charge OK?

Might be worth getting a trusted mobile auto electrician to take a look.

Be keen to know what it is when you find out!

Yeah correct battery, it's this one which was recommended to me by the guys over at R32OC:

https://www.tayna.co.uk/car-batteries/bosch/s5011/

Holding charge fine, and brand new only bought last week.

BlindedByTheLights said:

Tried this?

https://youtu.be/3qAZHIwIUDY?si=hK9IcgOKYq302qub

Thanks. I don't appear to have 40amp fuses in the areas shown in the video, a couple of 50amp instead but not as many. Guessing these differ quite a lot between the MK5 range and as this is an R32 I imagine they'd be different to the 2.0 TDI. All fuses in engine bay fine with none blown.


Think I have to admit defeat and get a mobile mechanic to take a look will update with outcome!

[BlindedByTheLights]

JRC1 said:

si_xsi said:

I wouldn't of thought replacing a single 20A fuse will either cure or hinder the issues you describe, I think fuse 36 in cabin is for headlight washers.

Presumably the simple things have been checked, e.g the correct battery type for the car, I'm no expert but am aware some need coding to the car these days. Is anything draining the battery when its connected or is it holding charge OK?

Might be worth getting a trusted mobile auto electrician to take a look.

Be keen to know what it is when you find out!

Yeah correct battery, it's this one which was recommended to me by the guys over at R32OC:

https://www.tayna.co.uk/car-batteries/bosch/s5011/

Holding charge fine, and brand new only bought last week.

BlindedByTheLights said:

Tried this?

https://youtu.be/3qAZHIwIUDY?si=hK9IcgOKYq302qub

Thanks. I don't appear to have 40amp fuses in the areas shown in the video, a couple of 50amp instead but not as many. Guessing these differ quite a lot between the MK5 range and as this is an R32 I imagine they'd be different to the 2.0 TDI. All fuses in engine bay fine with none blown.


Think I have to admit defeat and get a mobile mechanic to take a look will update with outcome!

Have you had a look on some of the R32 forums as I bet you’re not the first to have this issue. May also be worth buying some new fuses and trying them for a few pounds. I’ve done it and can be easy to miss a blown one if it’s not blown big if that makes sense.

[aka_kerrly]

May sound stupid but I find best practice when connecting a new battery is to put the live on first, then the earth and whilst doing that hold the unlock button on the key fob.

It may also be worth getting both keys (assuming you have 2) and putting one in ignition on 2nd setting then using the other to hold in the unlock position in the door lock as this helps to pair the keys with the ECU.

[Belle427]

I did read of someone that had the same problem, they disconnected both battery terminals for 5 mins, touched the two terminals together before reconnected and it came back to life.
Clutching at straws maybe but worth a try.

[JRC1]

Yeah I've tried that. Disconnected both terminals, touched them together, then re-connected. Exactly the same issue. And yes I put the live on first when reconnecting I'll try that suggestion with the second key although from everything I have read so far this sounds like a dash/cluster and then immobiliser issue rather than the ECU itself. The dash appears completely dead (pointing towards a blown fuse somewhere) and the immob is part of the dash hence why the car will start then cut after 1 second.

Also been on the R32 forums and have posted the same thread as this one. Lots of old useful threads out there too but all suggest similar things to what I've tried/what you guys have suggested.

There is a fuse box near the battery that has some much larger looking fuses in it, I'm not sure how these are really checked?! . The fuses I've checked in the positions advised by people having a similar issue (engine bay fuse box, side of drivers steering wheel fuse box) are the standard see through type fuses which are easy enough to check. But this big terminal in the back near the battery, I am not so sure. I'll have a read up today.

Not able to get a mobile auto electrician out until the new year anyway so may as well try checking some more areas between now and then.

Any other fuse boxes on the MK5 R32 platform? I read there was a second somewhere in the engine bay but can't seem to locate it.

Thanks all for the help it is much appreciated.

[JRC1]

Thought I'd update this. Turned out to be the whole dash cluster that went. Found a local company that specialises in fixing/refurbing them. They said the MK5 platform is one of the most common ones they get in. Anything like the surge of charge from a new battery to even just trying to start the car on a really cold day can knock them out apparently. Refurbed, back in the car and working great. Albeit my wallet is a bit lighter than I'd have hoped from just replacing a battery!

[BlindedByTheLights]

That’s good news, enjoy the V6 sound once again!

[si_xsi]

Thanks for updating the thread, I had no idea mk 5s suffered from this, so useful to know how it can occur. I read somewhere with manuals, if you press the clutch in when starting on a cold day, it puts less strain on the alternator, whether or not that's true or not I'm unsure.