Can you answer the following:
1. Where are you connecting the red wire of the molex connector. Fluctuation of the 12V supply?
------
I have a dedicated power distributor for all aftermarket gauges as well as HFS-3 (based on a solid state relay) the feed to relay is from the battery (0.7m length AWG 4 wire). I did not test but doubt there is major fluctutaion - all the gauges on the A-pillar in the video use this feed as well and no flickering.
------
2. The serial number of the unit.
------
SN: 100626
------
3. Are you using the purple wire of the molex connector?
------
Yes, and the flickering is only when the hedlights are one (dimmed mode). When the headlights are off the gauge is lit with steady bright light (i.e. works perfectly fine).
The purple wire is connected to ILL output of the CAN-bus adapter for Alpine stereos (+12v out when lights on). I didn't check if there is any fluctuation on this output however and do not know which charge it is designed for. On the other hand I have a bunch of electronics hooked to this ILL out (incl. other gauges on the A-pillar) and it works perfectly for them.
Is there any significant current in HFS-3 dimming circuit (purple wire)?
------
4. Is your circuit board exposed? Condensation?
------
Nope, it's in the standard casing, located in the cabin (due to temp fluctuations some condensation si possible but not much I believe).
------
5. Check the gauge cable is secure.
------
Will do (but as mentined above all semms to work OK except the dimmer).
------
6. Open up the gauge and check the soldering of the RJ connector
------
Will do (as a last resort

)
------
7. Blockage will not cause the gauge to flicker.
------
Understood, 2 completely different issues.
------
8. We have not tested the system with vodka
------
Vodka is basically 40% ethanol, 60% water. I double-checked there were no additives in what I used.
I will check though if increasing methanol ratio would help (today after a night in a warm garage the system worked perfectly normal). What I fail to understand is why the "water level" indicator lights up if the whole issue is due to vodka freezing.
------