bobby1999c5

I had to replace my battery on my 2006 and I opted to put an optima battery in it. I accidentally hooked up the battery backwards, as the negative and positive terminals were on the opposite side on the new battery(yes, I know that I am extremely dumb to not check this and I feel really stupid to have to admit that I did this). I had it hooked up incorrectly for a second(the car goes crazy when you do this...it continuously honks the horn, turns the wipers on, etc). Once I realized what I had done, I hooked it up correctly and it says Charging System Fault. I've checked the fuses underneath the hood and in the floorboard and the only ones that I saw blown were the radio/hud fuse and the HVAC blower fuse.

Does anyone have any suggestions on where I would need to look next?

Thanks,

Bobby

knkali

does the car start?

bobby1999c5

yes, it does. Starts and run fine, just doesn't charge and the volts gauge says 11.6 because it is running on the battery only.

Sparo2

Have you checked the volts coming out of the alternator? You can check this with a voltmeter from the power wire coming from the back of the alternator. It should read around 14.3V.

Also, have you driven the car around?
When you do, does the volts change?
While having the car idle, does the voltage change when you rev the motor to 3K?

bobby1999c5

Just checked the volts on the bolt on the back of the alternator and it says 11.3 when the engine is running(12.1 with the engine off because of the new battery). The voltage does not fluctuate at all when driving the car around or when revving the engine. When I left the auto parts store, it was at 11.6 and steadily went down over time as I drove home.

I really appreciate you all trying to help!!!

bobby1999c5

With the alternator not showing any voltage coming out of it, I would think that it would be bad, but is there a voltage regulator or anything else downstream that would have change how it charges the car? I don't want to change an alternator if I don't have to.

Sparo2

You don't have to change your alternator...at least not yet. You can take it off and take it to AutoZone, Kragen, etc and have them test it.

satans csex

Before you take out the alternator, check to see if a fuse is bad. Next I would locate the starter "near the passenger header" and check to see if the main power line that connects behind the starter and make sure that the wires or the 13mm brass stud isnt melted or loose. I would also check the 3 pin connector behind the alternator with a test light to see if they get signal. I dont recall 100% but you should be able to make the alternator charge by the ground of the test light so keep a volt meter on the battery to do this test. let me know how it goes

c54u

just a hunch but it could be a fusible link wire that is giving you a problem. i would guess it would be the one from the alternator to the starter

here are some posts to check out

http://forums.corvetteforum.com/c6-t...n-failure.html

http://forums.corvetteforum.com/c4-t...res-links.html

keep us updated

Coldmale

For sure its the fusable link

Take 7 feet of 2AWG and wire directly from the alternator to the post at the side of the fuse box. Run this back around the firewall out of the way.

Disconnect the fusable link wire from the starter but leave the wire to the starter from the post

I'd be surprised if that does'nt solve the issue

John

bobby1999c5

I've identified the cable coming off of the battery that you all are talking about. Do you all know what end of the wire has the fusible link in it(I saw a suggestion to solder in a fuse of the correct amperage, though I probably won't do this)? I understand that this may be the problem, but wouldn't the alternator at least have a reading at the post on the back of the alternator? I won't be able to get the car up on ramps until this weekend to follow/replace the fusible link wire or look at the starter wires.

Thanks,

Bobby

martysauto

Does your horn work? if not check fuse 2 in the underhood fuse block, this is for the horn and alternator. If good, make sure that you have 12 volts to terminal D (from fuse 2) at the alt 4 wire connector. Next, disconnect the 10 guage single red charge wire (with the battery disconnected). make sure it is secure, tie it to something so it won't short out. then reconnect the battery and see if you have 12 volts on the red wire. If you do, the fuse link is not burnt. if you don't have battery voltage, leave it disconnected and attach a seperate 10 or 12 guage wire directly to bat+ and the alt. Start and see if it charges. If this does not expose the problem, you may have damaged the alt or ecm.
PM me if you need more help.

bobby1999c5

Just wanted to say I really appreciate all of the advice. I tested the three wire connector and I had 12 volts, the horn does work, I checked all of the battery related fuses and nothing is blown, and I took off the wire to the back of the alternator and I still get 12 volts there too, so I don't believe that I've burnt the fusible link. If I have time later this weekend, I will take the alternator out and have o'reilly test it to make sure it is working. Is there a particular signal that it needs for it to charge. One suggestion was to ground out one of the wires on the three wire connector and this should signal the alternator to charge. Which one of the three would signal this?

Again thanks for everyone's help!

Bobby

Coldmale

Bobby

What I have suggested you do will take about 2 hours with the car on stands

It will cost about $10 and should be done regardless of any other problems. Please do it.

The fact that the fusable link may appear to be working when its cold, does not mean it will work when it is hot. That is the crux of the problem. It just does not do its job of protecting the starter.

Just get rid of it

regards
\
John

martysauto

How does that fusable link protect the starter? It looks to me that it is there to protect against a fire if there was a short on that circuit. Please explain.

Bill Dearborn

In this case the fusible link probably allowed more current than the rectifer bridge could handle and some or all of that bridge became the fusible link instead. With the battery reversed the diodes were all forward biased and current flow was probably more than they could take and they let their smoke escape. Then you also have the issue of the supply voltage to the regulator electronics being reversed which usually lets the smoke escape from those modules as well.

Here is the schematic for the charging circuit:


Bill

bobby1999c5

I had the alternator tested at Oreilly and the machine failed it so I am getting a new one Wednesday. Is there any other parts that you think could have failed that I would need to look at?

Thanks,

Bobby

vetehead

Assuming you have no check engine light and no codes have thrown I would say no,but the turn on circuit to the alternator is from ecm and the duty cycle is also from the ecm.The concern being the back feed during the battery reversal frying those circuits in the ecm....Hopefully not assuming you have no codes except the service charging system in the dic...Good luck

martysauto

More than likely he will have codes. I think he should swap in a known good alternator as long as the other testing points to it. Then light it up and see if it charges. He should also scan all modules for codes and record then clear them. I'd be surprised if the smoke is out of the ECM.

carlrx7

ouch, costly mistake, i bet you wont do that again!