it all started before i parked my 92 camaro RS for the winter. I was driving and my volts started going down, radio shut off and turn signals hardly worked. I took the battery and alternator to be test and they checked out good. i then had the alternator checked while under a load in the car and was only putting out 30 amps of the 105 its suppose to. so i got a new one and they checked it again when in got the new one and nothing was charging. now that i put the new one in it still is draining while i drive. If i have my lights wipers radio and heater on it will go down to about 9 volts. if i turn everything off the volts will go up a bit but not past 12v while driving. Any ideas what is causing this. My brother said it was he had the same problem in his 88 iroc and it was some relay under the dash that was bad. anyone know what this would be???

 

Ok, what you need to do is start with a fully charged battery that is load tested and checks out good, since you have a "good" alternator you are good there. Then disconnect the positive battery lead. Then turn your key to on position. Get a decent multimeter and switch it to DC amps. Put one lead on the positive post, and the other on the disconnected positive terminal. That will complete the circuit. Then look for amp draw....it should be a very low number, close to zero. If it is not, you'll need to check each circuit. To do this, test with the fuse in, then remove. Lets say you are drawing 6 amps with all fuses in, but after removing the lid fuse it goes to zero...that is a bad circuit. Could be a bad ground, but more likely a bad relay, or something is touching. FYI on an 88 iroc the hatch release relay is up there, so most likely that was the bad one. If you've stored over winter out side it could be mice.....so it may be multiple circuits. Best of luck.

 

or remove the negative terminal on the batt, hook a test light in between the removed neg terminal and the battery. start by unplugging the alternator. then start removing fuses. the light will go out when the circuit is found. i still believe it might be the battery.

 

You guys both described how to check a draw that draw down a battery over night. He is saying he is drawing down the battery while he is driving. Let say everything that is turned on adds up to 30 AMPs and your alternator can put out 105 that would mean your draw would have to be like 75 AMPs. There are only a few circuits in the car that can handle that kind of power and not fry a fuse or catch on fire. That is the starter circuit and the charging circuit itself.

There is more chance there is a issue with the wiring to the alternator or you got another bad alternator.

 

True, looks like I didn't read his post carefully. Even so, performing one of the over night tests would pretty much limit it to either starter, bad grounds, or a charging system failure of sorts...

 

What kind of a "load"? The amount of amperage output from the alternator is based on the demand on the car's electrical system. Meaning, your 105 amp alternator won't be putting out a constant 105 amps if the battery doesn't need it. It sounds more like you may have a wiring issue; bad positive or ground connections, or the exciter wire isn't working. With a small screwdriver through a vent hole on back of the alternator, you can ground the back side of the voltage regulator to the case. If the alternator goes into full charge mode (you'll hear it), and the gauge in the car pegs, you'll know it's either a voltage regulator problem, or the voltage regulator isn't being told to activate. Have you checked for power at the exciter wire?

 

check and replace the engine ground wire first as they are usually neglected and can often break off. that will eventually lead to other issues if ignored. after that, check or replace the charge wire from the alt to the battery. also, check that the regulator (aka exciter) wire that plugs into the alternator. a little corrosion or dirt on that can cause issues.

 

not sure on your car but my 1992 rs has a block that has all the main battery wires going to it between the radiator and the battery. see if all those wires are in good connection. and also check to make sure all those wires have good voltage as most of them have fuseable links on them. mine did but i got rid of all the fuseable links and put in one 60 amp fuse.

 

BAD idea. Fusible links are slow blow, fuses are not. A fusible link can take a momentary short or surge without burning out, a fuse that's rated according to a certain sized wire will blow instantly. There's a good reason why a fusible link is used how and where it is, and considering it the same as a fuse is a mistake. The purpose of a fusible link is so the wire it's attached to won't fry (the link is thinner than the wire), it's the sacrificial lamb of the wiring system. But, a 60 amp fuse is way over rated for many of the wires you're trying to protect. In the case of a short, the wires could melt, and a fire could start before that fuse decides to blow. Carbeques aren't a pretty site.

 

especially if its the starter wire....that pulls quite a bit, but probobly wouldn't blow a 60amp fuse, lets say somehow it drew 45 amps....it will melt.