Driving along the M11 on Sunday, headlights on... Got a surprise, it looked as if the batter, timing belt, oil and check-engine lights on the dash were going to come on, at the same time. But they had a think about it and gave up (?). Literally a 2 second thing. Started to get there but not quite and then just went off. They never got to full bright ON.
Wondering what that might be? Alternator ?
The trucks been doing about 120 miles a week, entirely motorway traffic, starts on the dot. The main battery in 16 months old, the leisure battery is on a ctek d250 , and is well over 4 years old (and due a replacement) it barely holds voltage. (This is a 12v system, factory shipped with 1 passenger side battery ).
What could it be ?