So after swapping the engine in my car I've noticed the infamous headlight/dash light dimming problem. Lights are fine at idle but will dim under power. I've read tons of other threads with the exact same problem but none with a solution.

http://m.hondatech.com/showthread.phpt=2021069&styleid=18

This guy cut the altc wire and the dimming went away but that seems " rigged. "

I have a new battery that's been tested, tryed two different alternators, and checked all the major grounds.
Any input would be awesome

2000 civic ex w/ 97 spec b18c itr swap.

 

Convince me that these^ two alternators were good and matched the car.


Be specific.

 

What voltage and amperage is your alternator putting out? What size battery do you have installed? Any other electrical modifications? Is the CEL on? Does it work?

 

The first alt was off of my d series which I never had a problem with. Had that one tested at auto parts store, don't remember the exact result but it was working correctly. The alt that came with the swap was tested on the car last night and didn't go below 14.01 under load.
I cleaned and sanded the connections for the 3 major grounds on the engine and the ones in the fuse box under the hood.

 

The current alt was at 14.2v no load and 14.01v under load. I have the regular "small" civic battery. No electrical modifications at all, and no CEL's. The cel does work for sure.

 

When you turn the key from off to ON(II), does the cluster battery light turn on and stay on?

 

You will usually learn nothing from such a test when the problem (lights flickering) is not happening.

How frequently does the problem occur and under what conditions?

 

Yes. Battery and oil light

 

I really only notice it once the car is warm. The test last night was while the lights were acting up....

 

And you didn't note any voltage fluctuation?

 

But that was at the auto parts store. I plan on testing it tonight with a multimeter. I just tested it cold and got 14.32 and 14.19 under load...

 

If you don't detect voltage fluctuations, then the light switch may be bad. Try cleaning the electrical contacts.

 

Will do. Thanks a lot

 

Do you mean the headlight switch on the column?

 

yes

There's a DIY in the FAQs sticky.

 

So, to update the thread...

The car in question was totaled, (hit and run, some ******* in a minivan,) so I never got a chance to fix the dimming issue. This past week I swapped the engine/trans/harness to a new shell. I also bought a high output 140 amp alternator to go with.

Moral of the story, new car with same swap and same problem. This leads me to believe that my problem is somewhere in my harness. I plan on pulling the harness, stripping all the loom and inspecting it.

Meanwhile if anyone has any other ideas, let me know.