where to look for intermittent issue

[TransitKamper]

hi,

i have a 2.4tdci rwd 5 speed euro 4 2008 van. intermittently at totaly random intervals the lights will come on the dash, accompanied by a momentary loss of power (albeit for about 1 second) the van continues running/driving uninterupted and 3 seconds later all the lights go out and the van drives absolutely as normal. i drove for 1 hour and it did it 6 times, but then again i drove from ullswater in the lake district to sheffield and it didnt do it once.
no warning lights or faults showing .


i have forscan, but as you guessed, im new to this, does anyone have any pointers for me. where should i look as this sounds to me to be an electrical issue,

i need this sorting as its a campervan and we cant be risking breaking down .

i really hope someone can help me , as i know if i take it to a auto electrician, its not going to develop the fault for at least 4 days

[f-wolf]

Bad Earth somewhere ??

[boosted_diesel]

Which light exactly come on?

[TransitKamper]

Oil engine management battery maybe another but can’t remember . But then in 2 /3 seconds it’s back to normal.

[boosted_diesel]

Yeah I would check the engine ground first then as f wolf says above. As that could cause all of those. Does it ever hve any issues cranking well?