Battery drain

[72 5500]

Searching for what is causing my battery to drain. Anybody else had this problem?

[Gotenntitans]

Our 1990 GMC drains battery if we don't cut the ignition key off twice. To avoid draining the battery, we have learned to kill the engine by turning the key off, then turn the key to the point of the radio playing and gauges working, then turn the key off again. Took us a while to figure out that upon initially turning the key off, the engine would stop, but the dial style gauges would stay in position. The second key turn lets the gauges roll back counterclockwise to zero position.

Any one time on this same truck, the brake lights would stay on and we only realized at night that they weren't going off. That was a brake pedal adjustment and hasn't happened since. GTT

[pwdcougar]

Originally Posted by 72 5500

Searching for what is causing my battery to drain. Anybody else had this problem?

You can pull the fuses one by one and check for current draw with a multi meter. I can't remember the exact way to do it at the moment though, I've got a bad case of CRS.

Paul

[speedygonzales]

Unfortunately most people have blown the fuse in their multimeter so it won't read current draw. Not realizing the fuse is blown, when they look for what should be no current draw. They always seem to find it's normal. You won't have a tester like I made to check the fuse each time I went to use the meter with a car battery. You should remove it from the meter and test if with the ohm part of the meter. The meter will still work for resistance Ω since the fuse you took out is only for current.

Incidentally, there are usually 2 fuses, one for each of the 2 scales.

The meter goes in series with one of the battery cables and the battery. If you take off the positive cable, put the meter leads in the right sockets on the meter for current. Start on the high scale, usually 10 amps. Put the red lead on the positive terminal of the of the battery and the black lead on the positive battery cable.

If the meter reads lower than the low scale maximum on the meter, switch to that scale. For example if the low scale is 2AMPS and the high scale is 10 amps and on the high scale you read .3 amps, switch to the lower scale.

Now that you have a reading you can pull one fuse out of the car at a time and check the meter each time. Continue to pull fuses until you find the one that removes the draw as read on the meter.

If you have added any audio equipment, start with that circuit. Same with an alarm.