my headlights dim when i hit the brakes???

[forsakenfew]

if it ain't one thing it's another.

put a stereo in my car, and had problems with it cutting out at strange times. when i hit the brakes, when i accelerate, when i decelerate, etc. i made sure the ground was GOOD, and just to make sure i was getting a good power supply, i temporarily ran the power directly from the battery. still cuts out.

well, tonight i noticed that even my headlights dim a bit when i hit the brakes.

does this sound as simple as maybe a short somewhere in the brake circuit? would that cause these symptoms?

the car is a 60 catalina, and is running a brand new internally regulated alternator. no charging issues what so ever.

electrical sure as hell isn't my strong point. uh, i actually don't know WHAT my strong point is!! http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

[DrJ]

Do you have a ground strap from the engine to the frame?

How do you know, how have you tested that it's charging correctly?
Have you hooked up a volt meter between any hot wire and ground and get 14-1/2 volts?
That's what it should be.

[Fat ASS Whitewalls]

AS DrJ says, check the voltage. Did you be the alternator from a cheap parts store such as Kragens, Grandauto (RIP), Pep Boys, ect. I bought an alternator from Kragens, and went through 6 of them until I bit the bullet and bought one from an electrical shop. Haven't had a problem since. Dean

[59BuickWagon]

Did you have any problems before you put the stereo in? My cardinal rule is to check what you did last first.

[lownslow]

dont use the brakes ........ http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

[Rocky]

Sounds like a classic symptom of a bad body ground to me. Scratch a bare spot on the firewall somewhere and run a jumper wire directly to the negative post of the battery. Try it again to see if the lights still dim. If so, do a load test on the battery.

[Rix2Six]

I think Rocky nailed it. That's what I'd try.

[Fat Hack]

I'm just about done re-wiring my old rustbucket, and I thought of the ground issue well before hand!

I'm treating it as if it were made of fiberglass...running an adequate ground wire to every component, along with a thick ground strap between the engine and body.

What I did, was to make an aluminum "junction block" to handle the ground. It's only about four inches long by one inch wide and a quarter inch thick, but I drilled and tapped the center of it for a 3/8" bolt that provides a mounting point for a heavy battery cable under the hood, the other end of the short cable will be bolted to the engine. The junction block is where I've hooked up all of the ground wires for my tail lights and brake lights, and the gauge lights. The headlights will be grounded directly to the battery, and of course, the negative battery cable will connect to the engine in the same location as the heavy cable running to my ground block.

The junction block is mounted to the firewall where the old heater control valve went, and actually serves to ground the body...but I don't trust all that rusty steel to provide a good ground everywhere, so my "auxillary" ground wires provide total insurance!

Overkill? Yeah, probably.

But since many electrical headaches can be traced back to a faulty ground in the circuit, I'd rather take the time to ground every component with it's own dedicated wire than to waste time later chasing gremlins!

On another note, dimming headlights can also be a symptom of insuffecient alternator output, or resistance in the wires to the lights. That resistance can come from bad connections, oxidation, frayed wired, or wires too small to carry the current required.

But, as with other guys here, the radio problem would make me think a bad ground is at the root of your troubles with the car!

[forsakenfew]

ah, gentlemen.....thank you! i was thinking it was something along those lines. just took a look and there is no ground strap between the block and firewall. will put one in today.

as for the alternator, i bought it at an auto electric joint in town. good quality product, and the shop guy in back i bought it from is also a pontiac man, so he walked me through the install.

i'll let y'all know what happens. thanks again!

[uncleAud]

you don't really need a ground strap from your motor to your body. The acclerator cable will do the same thing...thats a joke incase someone takes me serious and the only thing that makes it funny is the element of truth...couldn't figure out what melted my cable!!!

[Mai Ki-Ki]

I had exactly the same problem, but found out my generator isnt charging enough, even after cheaning it out and such. SO it's alternator time for me, too much load on the poor old thing.

CHeers

MAiki

[forsakenfew]

PROBLEM SOLVED!! bought a 1.50 braided ground strap, installed, and low and behold, no stereo issues what so ever.

i'll wait till it gets dark to check the headlights, but i'm thinking i'm good to go!!

thanks to all who offered help.

[Digger_Dave]

[ QUOTE ]
you don't really need a ground strap from your motor to your body. The acclerator cable will do the same thing...thats a joke in case someone takes me serious and the only thing that makes it funny is the element of truth...couldn't figure out what melted my cable!!!

[/ QUOTE ]

Consider yourself lucky. A friend of mine was starting his NEW motor for the first time and had forgot to run the ground strap from the body to the engine. The accelerator cable (stainless) took the full brunt of the electrical load and melted in the WIDE OPEN THROTTLE position. The engine "lunched" before he could disconect the temporary "hot" wire to the coil!!

He will be rebuilding the engine when he can afford the parts!! http://www.jalopyjournal.com/ubbthreads/images/graemlins/frown.gif