I have a completely stock 1989 Honda Civic with 1.5L 4 Cyl and 5 Speed Transmission and 100,000 miles (I've had it since new). I noticed at night that whenever I go into neutral, my dash lights and headlights dim. Then if I step on the brake, it dims another level. Also, if my blinkers are on, it dims and undims another level that sync's with the blinkers. If I rev it, everything brightens back up like normal.
I have replaced the Alternator with another OEM 60A alternator (Denso) since I can't get the genuine Honda part any more. I have also replaced the battery. I have checked and loosened and re-tightened the battery terminals and the main ground to the body. This still happens. I know this did not happen when the vehicle was new, so I'm at a lost at what is causing this.
I see that there are aftermarket higher amperage alternators available. Does an older car need a higher amperage alternator than stock just to deal with increased resistance in old wiring? Or am I missing something else?
Any advice you can give would be greatly appreciated! I have lived with this problem for years and no one has been able to give me a definitive answer!
Now I can't say what causing this for sure but hear me out..... A long time ago I got a Ford Focus and it was in good condition low mileage the like. Then out of nowhere my tail lights both go out. So I have them replaced no big deal. They go out again. Then after that the fuse blows. Then the car starts having all sorts of weird problems fuses blowing lights turning off randomly the radio shorting out and the mechanics I took it too couldn't figure out whats wrong. So I trade it into a guy who rebuild wrecked cars for a living and he said after he took the dash apart he found the wiring in the dash had MELTED together and that was causing all those issue. Then I put two and two together. We had a freak heat wave that summer and my car was sitting outside for the entire summer roasting in the heat. I'm mentioning this because electrical issues can sometimes be very difficult to figure out and would be even harder to figure out online.
This is how Scotty tests for draw in the battery and you can test the other parts of the car in a similar way. A voltmeter and the tools Scotty uses here would be a great place to start
https://www.youtube.com/watch?v=B__DqK90IIc
@jacksonishere
Scotty's testing video is for parasitic drain. I have no parasitic drain. My issue is when the car is running and dash lights dim.
Could be a poor ground somewhere.
After all these years that might be expected.
@jim5506
How might I find where the poor ground would be? Or if it's even a poor ground causing this?