Budshark

Hi,

My 73 will discharge the battery in 48 hours. Battery has been tested good. When running, alternator is putting 14 + VDC to the battery.

With car shut off, no lights are on, radio is off, etc. What I have found that seems wrong is that with everything off, I have battery voltage at the number 1 terminal of the alternator. I also have battery voltage at terminal 2, but I believe that is normal. When I measure battery voltage at terminal 1, that is at the plug, disconnected from the alternator.

Any suggestions where to look next?

Thanks,
B

Redhook98

Had a similar situation. The PO had dropped the steering column for some reason. When he reinstalled it, it pinched the horn relay wire in the ribbon cable. That enabled the relay to be on full time. The horn itself was disconnected. This would drain my battery over about 48 hours as well.

MelWff

you have to hook up an ammeter to the battery and look for a parasitic drain. Pull one fuse at a time till the drain disappears.

Peterbuilt

You should NOT have any voltage on field terminal #1 with the key OFF.
Terminal #2 has voltage with the key OFF.



73 Schematic:

https://docs.google.com/viewer?a=v&p...ZTM0ZDc1MWM5Ng

Budshark

So looking at the diagram, is it possible that I have a failed ignition switch?
Thanks,
B

Peterbuilt

Yes, the ignition switch may have failed or possibly just out of adjustment.

Is this a new problem or has it been a problem for a while?
Did this start after changing out the starter?

Pete.

Budshark

Hi,

This is a new problem. No components such as starter, etc have been replaced in many years. I have owned the car for 14 years, the starter was replaced about 10 years ago and has and still works well. Steering column has not been tampered with either.
Guess I will try to get to the ignition switch this weekend.

Thanks,
B

Peterbuilt

Jim Shea has published some very helpful instructions if you need them:
http://jimshea.corvettefaq.com/?p=1009

Bills17n72

im guessing your burglar alarm is the problem

7T1vette

Remove the negative battery cable and connect an Ammeter between the battery terminal and the cable (use the 10 amp portion of your ammeter and hook (-) side to the battery). If there is NO drain on the battery, there will be no reading when you make the ammeter connections. Otherwise, there is a current drain and you need to find and eliminate it.

Pull all fuses out of the fuse panel (mark them accordingly!). Connect ammeter as described above. One at a time, install the fuses...checking for a current drain after each one has been inserted. Leave fuse installed if no drain is noticed. Continue until current drain is found. Remove that fuse again and diagnose that entire circuit [with an ohmmeter] to find where/how power is flowing to ground. Remember that this fault can be in the wiring, the connectors or in the components (internal failure). The vast majority of such problems are wear-thru of wire insulation. Alternator, clock, radio and powered antenna are sources where internal ground faults show up.

jim in oregon

7t1vette..Has it right..except, respectfully..I'd suggest not to pull all fuses and mark them..Simply remove them ONE AT A TIME and watch the ammeter to see if that fuse removal eliminates the parasitic current draw.IF NOT, REINSERT that fuse back into it's proper fuseholder position and go to the next fuse..Much simpler than pulling them all initially and marking them.Jim

7T1vette

Jim..

Most of the time, either strategy will work. But, if you remove ALL of the fuses and still show a current drain, you know that the problem is with the primary electrical system and that everything downstream is fine. Saves a lot of wasted time.