Engine cut out when I use main beam.

[phil9560]

Hiya all.Yesterday when I flashed my 2004 Sprinter main beam I stalled and lost all dashboard power.After I few minutes the van would start and main beam worked without a problem.But even as an intermittent fault this is dangerous.Has anybody experienced similar ? Thanks in advance.

 

[Kev555]

Driving through Floods or heavy standing water by any chance Phil?

 

[mioba]

have you removed undertrays

 

[phil9560]

No weather was dry.But I think I've found the problem.I have a battery isolator switch on the neutral fitted in the cab.This switch has developed a fault and isnswitching itself off.So I think I used the main beam with headlights and fan running whuch was too great a load with no neutral.Hence the shutdown.Does this seem viable ?

 

[Kev555]

Good find Phil, If you lost all 12v power that seems a reasonable explanation, either replace the switch or bypass it to test the theory out. When you say neutral I take it you mean the earth lead?

 

[phil9560]

Yes the earth.Beyond the basic principles auto electrics are a mystery to me.The testing and elimination process begins next week

 

[phil9560]

Problem solved.It was the dodgy isolator switch.

 

[phil9560]

Heres a question.Because I'm using the isolator I keep losing my radio station memory.So I connected the ground on the radio directly to the ground side of the isolator thinking this would solve the problem whilst leaving everything else dead.Instead it woke the whole system up as if the isolator was switched on.Am I missing something obvious ? Thanks.

 

[Blobcat]

Heres a question.Because I'm using the isolator I keep losing my radio station memory.So I connected the ground on the radio directly to the ground side of the isolator thinking this would solve the problem whilst leaving everything else dead.Instead it woke the whole system up as if the isolator was switched on.Am I missing something obvious ? Thanks.

I have a 10a fuse across my isolator so memories stay live. The fuse blows if you try and start the vehicle though.

 

[supernoodle]

Heres a question.Because I'm using the isolator I keep losing my radio station memory.So I connected the ground on the radio directly to the ground side of the isolator thinking this would solve the problem whilst leaving everything else dead.Instead it woke the whole system up as if the isolator was switched on.Am I missing something obvious ? Thanks.

The whole vehicle metal work is a ground, The radio will likely have some other connection to this ground, either through the case or some other input circuit
So that ground wire for the radio you installed will now be completing the circuit and carrying all the current for everything when that isolator is off...If it doesn't blow or melt something else will.

Blobcat's solution is safer.

 

[phil9560]

Thanks all.