Help wiring a light bar with automatic headlights

Toroz06 said:

In this case the truck already has s1 and s2 prewire with 12v ignition

Click to expand...

Okay, you only mentioned S1, so I wasn't sure.

Then you could use the two relay circuit shown in post #16 by wraujr.
(Note that the diode at the output of SW2 is not needed.)

Addendum and Edit:
If you wanted to build a small circuit using using only one relay (SPDT or SPST) with a couple of transistors, the circuit below should work:
The LTspice simulation shows the operation--
With S1 closed, the Light Bar is energized (blue trace) when the High Beam's voltage is there (both needed).
With S2 closed, the High Beams go on whether S1 is open or closed, and independent of the High Beam voltage.
There is also no feedback voltage from S2 to the High Beam circuit.