How To Test For Draw On Battery

For a long time I've had a problem with the battery in my Ford Ranger dying when information technology sits for a few days. I finally decided to exercise a parasitic draw test and run into if I could find the source of the problem.

Note: ** Brand sure that your battery is fully charged before you lot starting time.

To exercise a parasitic draw test you'll need a multimeter that's capable of measuring amps.

Here you lot can see where I took my cerise test pb, and placed it in the '10A' port.

To get the Ranger set for the test, I opened the doors and used a screwdriver to shut the door latches so the truck would call back they were closed, and to shut off the dome light. On older Rangers you lot'll have to find a fashion to hold the door pin closed in the door jamb.

I removed the (-) bombardment cable and hooked the meter in parallel between the (-) bombardment post and the (-) battery cablevision.

I had to use a pair of wires with alligator clips to connect the probes of the meter to the battery and cable.

Information technology's non pretty, merely it works.

With the dome calorie-free off and nothing on, the meter showed that the bombardment had a 0.28 amp draw.

You cannot outset the test here. Some people will start pulling fuses looking for the reading to drop, and blame information technology on the fuse for the instrument cluster. You have to wait a adept 45-lx minutes for the battery saver way to kick in.

After waiting and checking back, the amps had dropped to 0.12 amps.

I believe the normal adequate range is 0.01 – 0.07 amps. This is where people will offset pulling fuses and relays trying to find the faulty excursion.

Where To Offset – Aftermarket Accessories:

For me, I got lucky. I decided to start with the accessories that I had added to the truck. There are a couple of relays that operate my off-road lights. Upon pulling the fuse to the 2nd relay, my amp draw dropped to 0.01.

Even though the lights worked, the relay was faulty and causing a drain on the battery. I replaced the relay and still only had 0.01 amp depict.

Fuses & Relays:

The adjacent pace would exist to pull fuses ane by one until you see the amp draw on the meter drop.

You'll need your owners manual to look at the fuse box diagram so you know what the fuse controls (circuit). If you don't have an owners manual, you can download one at https://www.therangerstation.com/manuals/ .

You tin also expect at fuse box diagrams online below:

1983-1992 Fuse Box Diagrams & Checking Fuses
1993-1997 Fuse Box Diagrams & Checking Fuses
1998-2000 Fuse Box Diagrams & Checking Fuses
2001-2003 Fuse Box Diagrams & Checking Fuses
2004-2011 Fuse Box Diagrams & Checking Fuses

In one case you know what the fuse is for, you lot'll have to check each item on that circuit to see what'southward causing the amp depict.

It's not just fuses. The trouble can be in a faulty relay.

Suggestions:

Check all of the aftermarket accessories and stereo equipment that you've added to the truck first.

If your Ford Ranger has a factory amplifier as part of the stereo arrangement, check the amplifier circuit / relay.

I've besides heard of the problem beingness caused by a bad air conditioner relay. Every bit I said, if the circuit has a relay in information technology, be suspect of the relay.