Boost Gauge Install Light Issue

[Ajwit87]

On my 1991 tsi, I installed a mechanical GlowShift boost gauge. The gauge reads fine and no issues with it showing vacuum/boost. I have an interior fuse panel layout and realized that fuse location #2 has no purpose, but will give power on acc/on. So I run my wire to it. I found a bolt behind my radio, run my ground wire and bolt in. Test it, everything works great. I have all 6 available colors working on the gauge. Night time comes, I turn on my lights and it kills the light on the boost gauge. Turn headlights/running lights off, it illuminates the gauge again.

I have since moved my power wire to the radio fuse, then the cigarette lighter fuse. No matter which one I get power from, the same light problem occurs. FYI, all other lights and accessories work as they should. This is the only problem.

The ground bolt also grounds the radio there. So the radio and boost gauge obtain ground from the same spot, and the radio always works.

Do our cars kill power when the headlights are on to some fuses or what am I missing?

 

[ShadowTalon]

I have a Glowshift boost gauge and have it ground to a bolt (sanded to shiny metal). I have both that my Glowshift oil pressure gauge tapped into the power cable to the radio. I opted not to run to any fuses but I did solder all wires. Gauges power up whether I turn the lights on or night. They are the tinted gauges though so I don't care if they are always lit up.

 

[JFZERO ECLIPSE]

Try hooking it to the dimmer switch?

There are 3 wires from it.... Green on top is positive.... Black on bottom is ground... Try that

 

[Ajwit87]

I just figured it out. The ground wire that shared the same post as the radio ground was the culprit. I gave the ground wire its own source and its all working now. Thanks.

 

[ShadowTalon]

Great to hear you solved it. Usually when it comes to electrical stuff they tend to like their own ground.

Now edit the post and mark it as solved