My future step-son's 1992 Honda Civic LX has had a battery explode in the past week, battery light stay on, and then alternator fail. Car has 200k on it and I helped him replace the battery and alternator. The battery light is now off and the car starts fine but I told him there must be a short somewhere causing all these electrical problems. I showed him the old trick where you hook a test light up to the negative connection from the battery after disconnecting it and shove the sharp end of the test light into the negative post of the battery. If the test light is lit up, then you have a short and then you start pulling fuses until you find the circuit the short is on. The test light went off when the 50A IG fuse was pulled. Remember the car starts fine and Autozone and Advance Auto both tested the Starter, on the car, and said it tested fine!
Can anyone comment or help with this? I hate to see more things go wrong if theres a short in the starter.

Thanks in advance

 

The original problem was almost surely caused by the alternator overcharging the system.

What is the current problem? Does the new battery lose charge?

 

My first guess was that a failing alternator caused the issues too. I learned many years ago that usually with electrical issues, it's better to be safe and do some tests while you have things apart such as visible inspections on wiring and connections and the simple short test light test is always a good insurance policy.
Currently the battery (brand new)tests good
Alternator (brand new) tests good
Starter tests good

What concerns me is the short on the IG 50a circuit.
When you disconnect the negative cable from the battery and clamp the clip of the test light to it then shove or touch probe tip into the negative post of the battery. Now when you turn the ignition switch on the light should stay off. The light comes on when a hot wire is shorting or touching a ground wire somewhere.

Currently the test light comes on (connected to the negative cable & post)until IG 50a fuse is pulled! This tells me that there is power coming though on the negative side of the circuit.

I'm wondering what else is on this IG 50a circuit because I believe whatever is shorting out on this circuit may of caused the initial issues with the alternator and battery.

So the current problem isn't visible to the naked eye but hope to run this short down before it does anymore damage.

Thanks again

 

The 50A fuse protects the ignition switch, which should pull no amps when it's off. Test the ignition switch. It likely has continuity in the off position where there should be none.

Alternatively, somebody has tapped a power wire into the fuse 39 wire.

 

What's the best way to check the ignition switch for continuity?

 

See FAQs sticky.

 

Continuity for ignition checks out good.

Battery light has come on a few times today. Alternator, battery, & starter check ok at autozone. Test light still lights up when battery is disconnected with test light connected to negative wire and test probe touching negative terminal until IG 50a fuse is pulled which indicates a short somewhere in the IG 50a fuse...but I am unable to find short! I believe this mystery short is causing the battery light to come on and cause other problems.

Unable to find a #39 fuse per your previous message? Any other ideas what else could be shorting?

Thanks

 

Are you removing 50A hood fuse 39?

 

Yes, pulling the #39 - IG 50a would cause the short to stop. But that was before...now the short persists even when the #39 fuse is pulled! WIERD! I told my stepson to pull the whole fuse box and see if the short persists. Maybe the battery exploding and acid all around that fuse box caused the short?

Honestly, I'm not sure what's causing this short but the battery light is coming on intermentingly now.

Please let me know if you have any suggestions?

Thanks!

 

Check whether disconnecting the alternator wire from the hood fuse box eliminates the drain.

 

Disconnected alternator wire from fuse box and short remains.

Any other ideas?

 

Try again after removing the 80A hood fuse.

How many mA drain do you measure?

 

mA measured from battery positive & negative terminals with battery connected as normal?

 

All fuses plugged in -- Disconnect battery ground from chassis. Use a multimeter to measure the current draining from battery ground wire to the chassis.

Does removal of the 80A fuse eliminate the drain?

 

Ok, do check the mA with or without the disconnecting the alternator cable from the box?

 

Leave the alt cable connected, all fuses installed, and key off. Measure mA drain. Then remove 80A hood fuse 41 to see if drain reduces or disappears. If not, also remove hood 20A hood fuse 42 and 10A hood fuse 43 and disconnect the large starter motor cable -- measure drain again.

 

hi I had the same exact problem last night my alternator overcharged my battery and it exploded and acid got in my fuse box and now there's a short some where because I keep putting fuses and they blow.. did u ever find out where the short is?

 

No we haven't located exactly where the short is in ours. Actually are short is not blowing fuses and is a parasitic drain. I do know that ours exists in the Ignition circuit but haven't found the exact location within that circuit!
In my opinion, and I'm in no way a master mechanic, the first thing I would do if I were you is throughly clean up all that acid and all the affected contacts. You can get some electric contact cleaner by CRC.
I purchased and it just arrived today the power probe 3 ultimate which is a must have if you want to find a short quickly. If cleaning everything up doesn't cure yours, I would find someone with a power probe to borrow or I bought mine on amazon for $100.
http://powerprobe.com/PP3.html

I will update this post with my findings tonight.