Engine electrical

[alexw68]

Hi folks. Been searching for my problem, may be the old corrosion issues at batter, fuse block, etc. Wanted to post the specifics to see if the experts agree.

Situation: Just bought car. Problem in days - yipee! 2002 SC2 133k miles. Anyway, no problems whatsoever until day 4. Car started fine, drove to store, classic nearly dead battery symptoms when attempting to leave. That is - dim lights that go nearly dark when trying to engage starter. So little power, no noise at starter. Call wife, get the car jumped (seemed difficult - took a bit of engine racing/waiting from running car.) Drove fine for about two miles, then while stopped at a light, brief engine stumbling then it died. Now there is zero electrical power. No dash lights, no dome light, nuttin! It's late now, car is on the other side of town, etc. Corrosion, or worse. Whatchathink?

[td1238]

Dim lights are likely an indication of a faulty alternator, or wiring to/from the alternator.

However, a car that's completely dead all-of-a-sudden is likely an indication of corroded battery cables. Clean connections at the battery well, and clean the other end of each cable--at the fuse box and at the fender (+ and - respectively).

Once you are sure that the cable connections are bright and clean, start the car by whatever means necessary. Then, with all accessories off, after idling for at least 15 minutes, check the voltage at the battery. It should be about 13-14 volts. If 12 or lower, then the alternator or its associated wiring (wire that bolts to output terminal) is faulty. If alternator output is good, turn on headlights and heater fan. It should still be able to maintain over 13 volts with those two accessories on. In my SL2 it maintains bright lights with all accessories on at idle. In any case the alternator should be able to maintain proper voltage with most of the accessories on at engine speeds above idle. If not, then it is on its way out and probably has shorted diodes or some other issue (worn brushes, shorted windings, etc.).

[SC2Sick]

Check the battery/engine ground going to the engine block where the engine/transmission meet. I had to replace mine a couple of times with similar issues. I usually saw my digital odometer flicker first before it would start doing that and it was a sign to address it soon.

[alexw68]

I went to get the battery out of it this morning. Didn't have many tools as it was a ways grom home. But I have seen better connections before at the battery. Might have had dielectric grease at one time. Nasty paste in there. Also didn't think the pos cable to fuse box looked very good. So cleaned them up including the nearby ground strap. I then had a bit of power. Charged the battery all morn to no avail. I'd say it's shot, too. Successfully jumped it and got it home. Will give all connections a good cleaning this weekend. Plus a new battery and charging system test. Thanks! You guys were right on!