Need some help please

[Hoop69Mach1]

With my 69 Fastback. I know I could probably go onto the 69 stang forums, but I feel more at home here. And think I could get a quicker response. Anyhow, this car seems to have an electrical problem. My headlights, tail lights and dash display are way too dim. I've changed the bulbs, changed the battery. Not sure if changing the alternator will do the trick, but am thinking of it as a last solution.

What do you guys think? Thanks.

 

[Mosesatm]

Certainly could be the alternator. Any auto parts store can test it for you. If it is the alternator the battery should be slowly discharging. Is the starter also starting to spin slower?

 

[Mustanger]

Is the dimness you're noting compared to before on the same car, or to a more modern car? Old Mustangs did'nt have very bright lighting in general .

 

[Mustanger]

... but if you truly do have a degredation in brightness, another possibility (apart from the alternator) could be to check the light switch/knob, sometimes with aging, they can go bad. Also do a general check of all connections to make sure they're all good (including grounds). Good Luck .

 

[68gt390]

Mustanger may have hit the nail on the head. I had the very same problem with my 390 CS. Dash lights flickering, dim and headlights going on and off. Checked the headlight switch and found 2 terminals burned completely in two. Replaced with a new light switch and problem solved.

Don

 

[Hoop69Mach1]

The lights do not flicker or blink they're just dim. Headlights are on just not real bright, same goes with the tail lights. My newly acquired CS lights are way brighter all around, thats how I figured I had a problem on my 69. Initially I thought it was just because the car was just older and I got used to it, except for using the flash light at night to look at the gages ;D

I'll see if I can check my connections tonight.

 

[nfrntau]

You might run it jumped to your other car (that car running). This way you will be sure to have full current to your system.

If it's still dim, start checking the smaller items mentioned.
If it brightens up with the jumper then it probable is a charging problem.

 

[rvrtrash]

If you have a digital volt meter, or access to one, measure the voltage at your battery with the car running. It should be around 14V. Then measure the voltage at the headlights themselves, again around 14V on the input and 0V on the ground side. If the ground side still shows a voltage, you have a bad ground. If you are under the battery voltage a lot, start checking connections and switches. Take two asperin for when you bang your head under the dash and call me in the morning. ;D

Steve

 

[case12]

Are the lights still dim at high rpm? Casey