Help! I've got a 94 Trans Am, and whenever I hit the breaks, my headlights will dim.

They dim for about 2 seconds, then will go back up to full brightness, even if I hold the break pedal in.

All bulbs appear to be in working order (headlights, and the break lights)

I was having some charging 'issues' during the weekend, my voltage was around 12, and it'd drop down to 10.5 for a split second, and all interior lights would dim. Since that one time, volt gauge has been at pretty much 13 solid.

The headlights will dim regardless of what I'm doing at the time, I can be in gear driving, or in netural, or with clutch in.

 

i doubt your charging problem miraculously went away...

maybe test the battery and alt to check output...probably one of those.

there are alot of systems running when you hit the brakes...abs, lights etc

 

Check wiring connections at the battery/alternator...
Have your battery load tested... Might have a cell going bad....

 

I'm having this issue with my 99 camaro v6. Battery is good, on it's 4th alternator. Mine will happen while braking or at an idle. the power guage drops down almost 0's out then if I hit the gas it's fine. I just bought a new positive battery cable... haven't hooked it up yet. I was told by GM that mine was bad due to my amp wire........ I figured what the heck. The wire runs $80+. I'll let you know if it fixes my problem this weekend.

 

That sounds almost normal. When air pump is running it will put strain on the charging system. Also the cooling fans really hit up the charging system...as well as the A/C. When I first got my car I vaguely remember it doing that. I upgraded my alternator -> battery wire to 4 ga and also upgraded my battery ground -> body to 4 ga. No more problems. The voltage gauge isnt really all that accurate either. Mine will drag down in the 11s but if I put a multimeter on the battery I read 14.2 constant.