lights flickering very slightly only when cold - 986 Forum - The Community for Porsche Boxster & Cayman Owners

If you watch the HVAC LCD and interior lights when the car is cold, you can see them flicker ever so slightly. The headlights do not flicker and I have maybe only heard the radio cut out once for about 1 millisecond. I've decided to check the current distribution box, but 1) Where the heck it is at? I have the group 9 circuit diagram and I can only gather enough from the pictures to assume the current dist. is in the trunk near the ecu. 2) Since my charging system check out fine (volt meter at terminals when car running), I am thinking a few other things: grounds (battery grounds are fine). Any specific ground that you can recommend I check first? Thanks

The ignition switch can cause all kinds of odd electrical problems since it controls the switched 12V power, you might try to check it and see if it is beginning to fail. When the radio cuts out is it at the same time as the lights, random, or when going over a bump? Mine occasionally changes inputs after a speed bump, if that is what is happening I do not think it is part of the problem. If the lights are operating independently of the radio it is likely something in the lighting system (perhaps a bad headlight switch) instead of a broader electrical issue. When you say interior lights, could you be specific, is it everything, or the instrument cluster, overhead light, button illumination, etc? Hope that helps you get closer to determining the issue.

The flickering lights are so unnoticeable that...get this...you wouldn't notice it until I pointed it out. I don't see any of the switch lights flickering, and the radio cutout may not have been a real 'cut out' like I mentioned. I was driving and once it stopped playing the radio instantaneously, like 1 millisecond or less. Maybe it was just static on the station. I see the flickering in the cluster LCDs and the HVAC LCDs, as well as the cabin interior light. It doesn't seem to happen once the car has been driven for 10 mins/is warmed up. After its warm I try to have a staring contest with the LCDs and as much as I've tried, they don't flicker after warm up. I have an idea that while the car is cold/the oxygen sensor heaters are on/whatever else is on during warmup, its drawing extra power and starving the interior lights and LCDs. Thats the only thing I could think of based on it only happening when the car is cold. I'll check the current distribution box because a similar problem was the result of some corroded contacts inside the current distribution box.

I've no doubt that you will come up with a brilliant engineering solution not previously contemplated by us Luddites.

If you have a complaint, take it up with a mod. Otherwise please keep your useless comments to yourself/in your own threads

No, I don't have a complaint, and my comments aren't useless as they serve to amuse me. Didn't think that big ego of yours would be so easily bruised. Just remember, you were the one that came swaggering in here talking smack about doing some "real engineering". As ye sow...

Nothing to see here. Move along. Ah - Sir, .... Madam ? - Keep moving along please.

Subscribed. Hopefully the answer to your problem will help me figure out why the lights in my Honda are flickering.

Thats because of your 2000 watt amp haha.But I just figured out the current distribution box is in the pass footwell. I will look hopefully tomorrow. On another note, it started raining on me when I was driving home with the top down and the seat warmers on. I drove faster to keep the rain in the slipstream

I'll take a wild guess and say the alternator/voltage regulator is at fault. Check alternator's current and resistance at both cold and hot temp and see if they match. Just a voltage check won't be conclusive in your case Another possibility is, if all previous mentioned is fine, then you have a bad connection or very tiny crack in a wire somewhere in the circuit (e.g. battery cable, alternator cable or a ground somewhere). When HOT cables/metals expand and that could explain why you are not getting the flickering when hot. A very tiny crack in the cabling/connection can produce this flickering crap.

"Ludds" LOL

I suppose I will update this thread...the new ignition switch didnt solve the problem, and now cruise control and the radio/gauge flicker are there. The flicker and radio cut out only happen once when I come to a stop and the car is cold (and I can hear the SAI pump turn on and then shut off a few seconds later). The cluster lights and radio flicker/cut out instantaneously and then come back. The cruise control is a new phenomenon happening. The light will come on when I turn CC on, but it will never activate (or actually keep the car cruising) and after trying to engage CC a few times, the light on the dash will shut off (CC still turned on with the stalk button). New ignition switch didnt seem to make anything better

voltage regulator. $50. You can have it checked when you pull the alternator. Not a big deal and lots of how to's available.

I get how that would cause the lights and radio problem, but why does the CC not work aas a result of the regulator?

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Did you ever figure out the cause of this electrical issue? A few months ago, aftermarket radio started cutting out off/on and I recently noticed headlights and some dash lights flicker very slightly along with it. Seems to get worse as the engine warms. And completely goes away as soon as the engine is turned off.

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There are numerous grounds on these cars. A Bentley manual will point them out. The grounding points for the HVAC is were I would look first. Bad grounds are the most common issue with electrics.

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Run a voltage drop test across your primary battery cables, Porsche has had a problem with these developing internal corrosion that cannot be seen but alters the resistance of the cable as the car warms up.