I understand what you're saying, but how would the head unit relate the the lights dimming? I haven't seen any problems in the system yet because I don't think the fluctuation is noticable yet through the speakers. I didn't see this problem before it went into the shop... I will call them on monday when they are open
You added an aftermarket HU and light dimming resulted...?
An aftermartket HU will have a much bigger amp internal than factory.
Therefore it will draw more power from the fuseblock.
If the factory wiring is aimed at factory then it will probably be smaller than necessary.
Correct me if I'm off but is sounds feasible.
You may not notice the fluctuation through the speakers because there isn't enough power to cause noticeable distortion at the moment but there is enough to cause visual effects through the lights.
No, I've had the head unit and speakers installed in the car for almost a year now on this is the first I've seen the problem. When I had my 500 watt sub amp amp installed too (pre-timing belt replacement) It wasn't seeing this problem. It wasn't until the battery had died 2 times and it had gone into the shop for work that I saw this problem. But I get what you're saying, I'm just not convinced that that's the problem, seeing as I have had the head unit and speakers for a year and haven't had a problem like this. I'll give this a shot though, I never really thought about the size of the wiring harness wires being a problem but I guess it can be an issue