was wondering if there is anyway i can get rid of the dimming of my dash lights when i turn on my headlights. they dimm since there h4 100w instead of the 55w halogen lights. it freaks me out. should i upgrade the alternator. or is there some other way!
thanks!

 

have you replaced the grounds on the engine and battery yet???

if they are dimming you have insufficent voltage, so fixing the existing electrical should have been done before upgrading the bulbs.

if you have replaced the grounds, then you will need to upgrade the alt

 

ok thanks icemark!

 

You can run another wire from the alt to the battery, this usually gives you about a 1.5v increase.

 

where are the grounds on a s5 (90 GXL)
I got a battery from sams club (crap quality) before I take it back, I want to make sure all my grounds are tight.

I am going to tighten the alternator belt a little. see if that helps

 

There are lots of ground, you're going to have to download the FSM to find them all. I hear a lot of people complain about the one that goes to the firewall that's just clipped on. Why i don't know, I had mine off for about a month and then decided it should be attached to something so it's attached the fuel rail, which isn't even the right spot.

 

... the stock wiring is that bad? I thought that the Lpost wire went straight to the starter and then back up to the battery anyhow?

They really are not crap quality, they just aren't meant to be discharged and recharged. An Optima battery upgrade won't fix your dimming problems, so don't think that a "crap" battery is an issue, I've had awesome experiecnes with $30 dollar batteries from walmart. I knew what to expect from the, and because of that had no problems.

A "crap" battery would be one that leaks acid all over the engine compartment, or one that doesn't hold a charge on a normal stock system...

 

I agree, both my sevens have sams batteries,

I found that my alternator belt need a little tightening.

I measured the voltage on the battery, 13v (good?)

next step I need to measure the volts across the battery at idle and 2k rpm.

one thing I did notice that when the lights in dash dim, my idle rpm also drops. to around 250.

FYI, I already scraped my battery posts clean and tightened both battery connector and sprayed some anti-corrosion liq on them.

 

have you checked the BAC to see its working well?, it may be unrelated, but it came to mind when you said the rpms dropped

 

IF the grounds are good, upgrading the alt might just fix ya up...You just socked it with an extra 90 amps, the stock alts weren't meant to handle that kind of load- you're lucky it hasn't "smoke checked" itself...