Dartster 66

cant figure out why when you turn on head lights or anything else the alt gauge drops to the negative side the more you turn on the further it drops I have replaced battery and voltage regulator had the alternator tested its fine! I did notice that when I was using a test light when I would touch anything metal I could see a small spark ! I have moved my battery to the trunk and put in a kill switch to the negative side! Have just about checked all of the wiring for a short no luck
Thanks any help would be great

RacerHog

Are you sure you have the gauge wired rite? Might have the wires reversed?

440roadrunner

Very first thing is, what the heck are you working on?? We need to know that because, well, we need to know that.

Have you checked charging voltage at the battery? This is first, after "FIRST" above

Does the ammeter ever show charge?

Many many possibilities here, just a few are...............

slipping belt

damaged alternator which is not able to put out full power

damaged connections in the charge path from the alternator to the battery which includes the terminal right at the alternator output, the bulkhead connector, the ammeter connections, back through the bulkhead

Faulty regulator

Wiring issues in general, loose connections, mis--wired, etc. Has the wiring been MODIFIED from factory??

Dartster 66

yes there is only 2 terminals on the back of the dash and 1 of them says red and my wiring schematics show hot going in and hot coming out I even when out last night and checked to make sure that they were not toughing the back of the dash even put some rubber on them to make sure they were not touching the metal on the back on the dash and looked over the gauge to make sure it was not burned up or something

Dartster 66

oops sorry its my 66 Dodge Dart Gt .Yes its get about 14.6 volts it only has 1 belt and its tight .took in the alternator to get it rebuilt cause its chrome they tested it and said it was fine and did not need rebuilt .voltage regulator is new as of last night .I will ck the wires at the alt again but I have replaced any and all of the wires that were broken or old and any wires that was not in use were removed as to not short out bye accident .and yes the car has been modified has MSD box and battery has been moved into the trunk has a newer fuse block put in it .the only thing that has changed is I put in an electric fan in and a battery shut off switch in. I have disconnected the fan and added a second strap to the neg side of the battery to make sure that it is grounded .Dose it matter if the ground strap is connected to the frame in the back of the car then connected to the motor from the frame ?

RacerHog

As long as your have good grounds... Chassis, Engine, Body, you should be good there.

Dose the gauge go to the + side after you start the car and give it some throttle? Or dose it go to the middle and stop there?

Dartster 66

the car has a three gauge set up in it to the amp gauge dose show charge when you give it gas but drops back down when u let off .and the alt gauge in the dash never comes back above to the + side

440roadrunner

You said the battery shows 14.6 which is actually a little high

Let's go over SPECIFICALLY what the ammeter does.

FIRST Get in the car, shut the door and make sure EVERYTHING is off including the dome light. The needle should be CENTERED

Now turn on the lights, the key, and the heater blower. The needle should deflect noticably to the NEG (left.)

Turn everything back off and start the car, let it run "fast idle" and if the battery is good it and has not been sitting unused for weeks, the needle should first go WAY over to the right "charging" and as the battery comes "up" the needle should drop back to CENTER. It should pretty much run "centered," dropping a little at low idle at a light, charging for a bit to get "back up" and then "cruising," should settle back at center.

"Cruising," turning on lights, heater, should result in the needle flickering a bit for a second or three, and then running "at center."

Stopping at a light, lights, heater on, normal for SOME systems and smaller / older alternators to show some discharge at low idle. As you take off from the light, it should show "charge" again for a bit, and settle back to center.

Dartster 66

ok sorry went out yesterday and cked the meter and it said 13.60 volts to the battery and the battery is a brand new optima and as long as the car is off and nothing is on the gauge sits in the middle if u turn the lights ect on running or not it drops to the neg side and depending how much u turn on it will drop even more
(lets say u have a gauge that shows 1/4 1/2 3/4 full the 1/2 being the off position-CENTERED when u turn on the lights running or not it will drop to the 1/4 mark and keep going the more u turn on )it dose not come above the center mark

Dartster 66

ok found the problem it is the back of the dash not sure if I going to say this right but .were you plug in 2 4 plug harness it has 4 male ends that is attached to the circuit board and 1 on each side (of coarse) is loose and u can see the bronze circuit board is chipped and missing some of the bronze stuff under the male end ! ok now the big question is can you buy a new one anywhere? Cause I know if I try to fix
this it will be in worse shape than it is now ???
thank you for all of your help

Dartster 66

turns out there was another load in the headlights too but found it too and maybe in old alarm system too will it ever end any ways thank you for all your help