Electrical fault??

[Plimplumb]

Hi everyone, I have a 2006 1.9d and am experiencing a few problems.
It all seemed to start with my radio. It started to randomly turn the volume up to max all by its self every so often. Then my two side rear brake light would not work. I changed the bulbs and fuse but it did not work. The brake light in the door is working fine so very strange.
Then when driving home I could hear this crackling noise and all of a sudden the engine cut out and would not re-start. I called the aa and they came out to me. The guy was great, he found my alternator cable had rusted through and snapped which he repaired. He said the starter motor had been burnt out as he could smell burnt electrics.
I bought a new starter motor which I fitted and the van started first time. Four days later the crackling noise came back and the engine cut out again and would not re-start!!!! I have removed the starter motor again and it smells burnt again although not so strongly as before.
I believe I must have an electrical fault somewhere has anyone experienced this before as I'm totally confused can anyone help????

[Ol'Jeffers]

It sounds as if the the starter motor is running on after the engine has started.
The 'crackling' noise may be the bendix gear engaging/ disengaging when the engine is already running.
I had this with a SAAB for rather different reasons but the outcome was the same....new starter motor!

[Plimplumb]

I have replaced the starter motor once already and it happened again within 4 days so I'm wondering if a have an earth fault??

[crickleymal]

Possibly or perhaps the starter solenoid is sticking on which will keep the starter motor engaged