Issue with aftermarket headlights

[Dmitri Mernenko]

Hello, just wondered if anyone had the same issue or can offer some advice on what could be the problem:

I’ve just had solar panels and a water tank installed. The solar panels are connected directly to the leisure battery and the water tank is connected to the van battery.

Here’s my problem: the light bulb warning light has come on the dashboard and the lightbars on my aftermarket DRL headlights don’t stay on when I switch to dipped beam. All exterior lights work. Lightbars work as normal when lights are off.

Any ideas what could be the issue and how to resolve?

Thanks in advance!