1995 Mercury Marquis Battery drains

RLANGWEIL

MEMBER
1995 MERCURY MARQUIS
V8
2WD
AUTOMATIC
11,700 MILES

Car was running great wife could not start after school, put New battery in, started ran great till next day when she was picking up kids volts dropped car stalled no starting power in battery. Took out alternator had tested on macine in three different places checed out ok, then took battery to get tested battery check out good on 2 machine. Tooked to shop they put it on diagnostic machine all the electrical components cheked out, they changed out the neg. Battery cable end, started up well left then went about 5 miles and it died on the driveway, I am lost for an answers. Please help

1 Reply

CH112063

MECHANIC
1,320 POSTS

Bring the new battery back. It may be bad.
Get yourself a 15 dollar voltmeter at Radio Shack. Put the dial on DC volts. Put the black negative lead on the negative side, then red to red and look at the voltage, 12.6 is a fully charged battery. Each of the 6 cells puts out 2.1 volts. Start it, the voltage should rise to 13.8 to 14.9 or maybe a slight bit higher. Now you know everything is ok. Overnight if it dies you hace something pulling current, just like turning a dome light on and leaving it. The cigar lighter, trunk light, hood light, any one of many acces. Could be failed. Something was turned on or failed, and could be draining the battery. If you have time read about how it works and is tested here at the different site menus like battery goes dead. It is common problem for the cigar lighter, or hood lamp switch to fail, be on, and you wouldn't know it. Take the lighter or bulb out or turn it off. Dogs and kids are good for turning things on accidentily. Have good day. Bye