02 LS electrical?

[Phatt_daddy]

My 02 v6 has a slight problem of 1. the headlights brightening and dimming along with the interior(gage, HVAC,and radio) all at the same time while driving at night and 2. the HVAC blower changing speeds as well..... Anyone have this happen before and what can I do to fix it.

Thanks,
Nate

 

[joegr]

Well, there are a few possibilities. It could be corroded or loose wiring somewhere (a battery cable or major power circuit or ground), or it could be you alternator is starting to fail. I think that the alternator is the most likely suspect. It is easy enough to confirm with a voltmeter and taking a few readings at different locations on the car.
Since you have a first gen, you really need to get the Motorcraft alternator to replace it. Most of the aftermarket does not seem to correctly understand the odd alternator control scheme that the 1st gen uses. Maybe this is why the 2nd gen changed to the more common method.

 

[RigsLS]

Myself, I'd start with checking, cleaning and tightening the battery terminals connections, take it from there ...

 

[Phatt_daddy]

Terminals are clean and tight. Alt was replaced a little over a yr ago (Dec 2015). The car has a sunroof that leaks....... Could that lend to part of my problem. As far as the headlights go, I also have a Grand Marquis I'm working on and over on Crownvic.net there is a wiring upgrade that can be done on those cars due to an intermittent voltage drop in association with the factory wiring being a gage too small..... Would something similar be feasible on these cars or is the wiring pretty good on the Ls from factory?

 

[joegr]

The wiring is a heavy enough gauge. If that were a problem, we'd all have that issue, and not just you. What brand was that alternator? Have you done any voltage measurements?