Adding panel lights makes the whole circuit dimmer??

I have a late MK4 Jetta TDI that has always lacked some of the dash buttons and lights that other Jettas with more options would've had, including heated seats and their respective switches, the traction control defeat button, and dash vent lighting (due to it being newer than a 2003). Since I previously owned a Jetta which had all of these, I decided to add all of these buttons and lit vents to my new one so I wouldn't have to stare at an empty-looking dashboard all the time.

I know, pretty pointless... Anyway, to make them all light up at night, I tapped into the power going to the rear-window defrost switch so that all the new lights would work off the main dimmer switch. I made the wiring nice and neat, with a positive and a negative wire going from the lines into the defrost switch to each of the lights, in a kind of hub-and-spoke fashion. I'm an idiot when it comes to electrical wiring, so that is probably the absolute wrong way to do it, which leads me to my issue... Ever since I did that, all the red and blue interior lights seem to not get nearly as bright as they did before. Do just a couple extra lights really draw THAT much power?? Or was there a better way to wire them in?





I know it doesn't look like it in the photos, but ALL the interior lights are much dimmer at night, and aren't even noticeable in the daylight. I appreciate any help!

Wow.... um... yeah, I have nothing to say. Other than it is pointless, I agree there.



Sorry I cannot be of any help. The current is done through the headlight switch, which is the same for all the cars. Maybe it is normal for the cars with more crap on them to be slightly dimmer overall, I never noticed.

A wiring diagram is certainly needed here. I would disconnect your mod before you burn something expensive up such as your ECU. The grounds for you added lights might be feeding power to your defroster heating element or to some of the other functions the new switches control.

Clearly to much amperage is being drawn through part of the lighting system than it was not designed to handle.

Once you put it back to stock, pop out your dimmer switch and try to figure out how it is wired and also make absolutely sure that were you tapped into the lighting on each of the new switches is actually for the lighting and not a user function of the switch.

Oh, did I mention it? A wiring diagram is certainly needed here.

Almost forgot. drawing additional current from your defrost switch lighting might melt the lighting wires going to it because those wires are are only designed to carry enough current to light just one bulb. Are the additional switches actually control anything, or are they just for looks?

The new buttons serve no purpose at the moment other than to make it look like I have heated seats (which I may soon add) and traction control. I did look at pinout diagrams of all the buttons, and only have power going to the pin that operates the little red LED's in them, and the ground of course. I wanted to wire them in with the rest of the lights so they would all be dimmable. I suppose tapping off the defrost button's power for ALL of them wasn't the best idea, but if I wired them all in parallel, would it really matter where in the dimmable circuit I put them?

Right now, the lights all turn on, they all dim, and I haven't noticed any signs of excessive heat being produced. They just don't get quite as bright as before :/

I guess I'll disconnect them for now in the interest of safety until I figure out how to do it properly. The added buttons and vent lights DO improve the look of the cockpit, especially at night, but yeah, they are completely unnecessary.

You might have a bad dimmer switch and the extra draw is just making it evident. Nothing too crazy about the MK4 dash lights, power goes into a rheostat and out to the lights.

I hadn't considered that.. I did replace the dimmer switch about 2 months ago with a slightly stiffer one from a junked mk4 golf. I'll have to put the old one back in and see if it makes any difference.

You have both the positive and negative spliced from the same switch? That's the problem. You need to have it wired in parallel, not series. The entire circuit is wanting to draw 24v now because of the nature of series circuits (voltage is additive in series but amp draw is constant, so i am assuming Two 12v lights) causing all the lights to not have enough voltage. Just splice the negative to a completely separate ground and it won't dim (parallel circuits keeps voltage the same but increases amp draw.)

Were did he say he wired it in series? Knowing exactly what he did would be very helpful.

My best guess is that he is/was grounding through the defogger element. If so, turning on the defogger would cause the dash light to go dark with the dimmer turned to full bright because there would be 12V on both sides of the light filaments.