Why "No signal" on reversing camera?

I'm hoping someone out there is technical. The reversing camera - Veba with 7" monitor which clips to the rear view mirror - is playing up. Two things are happening:
1. The fuse 25v which operates the camera + electric step keeps blowing. I have a stock for every journey.
2. I am now getting "no signal" when I switch on the engine. Sometimes I get a picture about 15 minutes later - sometimes nothing.

Is it broken? Is it wiring? Why does the fuse keep blowing?
Can anyone advise?
Jan

Hi, I'm guessing the fuse is 25amp, not 25v.
It would take quite a fault to blow a 25amp fuse, most unlikely with the low wattage draw of a reversing camera, so more likely there is a wiring fault in the circuit  to the electric step. It could just be a short circuit, possibly where the camera is connected?
I would start with a good visual inspection of the relevant wiring/switch circuits.
Jollywalker

I wouldn't know where to begin - so I'll have to put it for that inspection. When I change the fuse - the blown one has melted - so something is giving it a powerful blast. Is it safe?

JanWhitmoreMET wrote:When I change the fuse - the blown one has melted - so something is giving it a powerful blast. Is it safe?

Counter-intuitively, if the plastic part of the fuse is melted it generally ~doesn't~ mean that it's taken a very heavy overload. If it's melted, it typically means either that it has been carrying a current close to its rated capacity for a long time, or that there is a poor connection on one of the terminals and it has been arcing. If it's the latter then you will (assuming it's a "blade" type fuse) typically get a blackening of one or both of the blades.

If the rating of the fuse (at 25Amps) is in accordance with what the owner's manual says it should be, then it should be safe. The fuse rating is selected specifically so that it will blow before any of the wiring loom suffers damage.

However, if something is taking that much current for long periods of time, I would expect it to get very warm, if not hot. I would check the main components (especially the motor on the step) after the van has been running for a while. If for example the cutoff switch on the step is faulty so that the motor is sitting there powered on but stalled, I would expect it to get very hot indeed after a few hours.

Thank you mojo that is helpful and gives me more peace of mind. I'll keep it all in view...... and carry plenty of fuses. I think for a while I won't use the electric step and see what that does.

Any ideas on why I am all of a sudden getting "no signal" message on reversing camera?

Also it occurs to me why the reversing camera and step are linked in one fuse?

Confused.  The Veba is a mirror monitor which also works when the van is going forward i.e like a mirror in a car.  If it has been wired up for reversing only then it would probably use the reversing light feed.  Either way, nothing to do with the step.
Needs an auto electrician...  PeteJ

pjkxpjkx wrote:Confused.  The Veba is a mirror monitor which also works when the van is going forward i.e like a mirror in a car.  If it has been wired up for reversing only then it would probably use the reversing light feed.  Either way, nothing to do with the step.
Needs an auto electrician...  PeteJ

I can remember thinking the same thing when a similar problem came up in a previous thread, but for some strange reason, A/S apparently choose to use a shared fuse in the EM40 for these two different functions on some conversions. It's probably just that the EM40 has a limited number of fuse slots, but it does seem weird (to me at least) to use the same fuse for two such dissimilar loads. It looks as though A/S themselves may have reached the same conclusion, as the owner's manual for a 2013 Worcester shows the electric step on a completely different fuse, on the main Sargent fuse panel rather than on the EM40 - and it's only rated at 10A there.

Agreed, though - I would not delay, and would get an auto electrician to look at it asap. My guess would still be the limit switch on the step, but that's just guesswork - it needs more methodical testing.

If the electric step motor 'stalling' is the problem then running the van without using the step won't cure it. Effectively it means the step motor is trying to work but can't and that's causing an overload. In other word it isn't turning itself off when it finishes extending or retracting. That will continue until the problem is resolved. Hence the need for an auto electrician asap.

Following on from SDA's comment, if the step motor is still trying to operate there will be quite a large spark from the fuse/holder when you put in the new fuse.
If that is the case leave the fuse out!

bertb wrote:if the step motor is still trying to operate there will be quite a large spark from the fuse/holder when you put in the new fuse.

I think we're all guessing a bit here in the absence of more info (for example I don't have a circuit diagram for that model, and I'm only ~guessing~ at where the fuse is). But if I'm guessing right there will be no large spark unless the OP tries to replace the fuse while the engine is running.

I ~think~ what may be happening is that the limit switch that detects when the step is "in" has failed or is out of adjustment. So when the OP starts the engine, the EM40 circuit activates the motor to pull in the step (which may actually already be retracted), and then the motor continues to be powered, but stalled, until the engine is switched off. If true, this won't do the motor any good at all...

As you suggest, I personally would leave the fuse out until someone has had a chance to investigate - I would not repeatedly replace it when it blows.

Not thinking during last post ( too much HPA ) I Assume the monitor is a VEBA AV70MM.

2. I am now getting "no signal" when I switch on the engine. Sometimes I get a picture about 15 minutes later - sometimes nothing.


Does it go blank when the step fuse blows?  Does the step work until the fuse blows?


If the monitor displays 'no signal' or works intermittently then it must have 12v power so maybe be a bad camera connection. It may also have two separate feeds like our Warwick Duo which has a separate feed for reversing.
The camera is connected with a wiring harness which is either 10 or 20 metres long. On our 2011 Warwick Duo it uses simple phono plugs which are prone to a bad connection particularly at the cab end or corrosion particularly at the camera end.

I agree that any fault which can blow a 25 amp fuse need checking out ASAP.
PeteJ

Mine only comes on when in reverse. It would be nice if it was on all the time though. This is on a 2013 Dorset but same camera/monitor.

I'll give it a try. I have not tried that with the ignition on! Doh!
It worked.
I did think it was a bit limited operation, only used for reversing.
But I am still getting reversing sensors fitted, only 2 mirrors to watch.

As I have a 2011 Worcester that has had somewhat similar problems in the past, I could offer a few suggestions that may give some help.

A search under "Sargent Intelligent Interface Adaptor" on the forum will give you a summary of difficulties in this area and members various inputs.

I am assuming the fuse blowing problem you have is in the EM50 unit behind the driver's seat. Although it is darned difficult to see this box without unscrewing it from the floor, the relevant ones should be,
F5 20Amp Electric Step
F7 20Amp Fridge supply from alternator 

However, certainly in my case the F7 fuse also supplies the reversing camera- the logic behind this being that both need powering up only when the engine is running. As the fridge takes 12 to 15 amps then obviously this is the dominant load compared to the reversing camera needs. Could you have an intermittent problem with the fridge? Would it be worthwhile running with the fridge switched off for a period (if convenient) to see if the problem occurs?

You will see from the earlier thread that my initial problem was with the electric step. It took a long while to find that the cause was a switch on the back of the step that had (inevitably) suffered moisture ingress and caused the relay in the EM50 unit not to operate properly to change the drive direction of the step motor. 
In the interim, I had had various fuses out of the EM50, one of which  was F5 feeding the fridge/reversing camera. Not having replaced it firmly enough (due to its position), resulted in a high resistance contact in the fuse holder and because of the high current this caused overheating and melting of the fuse plastic (familiar?).

Sorry if this is a real ramble and although your problem may have nothing to do with my experience, it did sound very familiar. Hope it is of some use.

Graham