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2.3L ('02-'11) 2003 ford ranger battery keeps draining


03rqnger

New Member
U.S. Military - Active
Joined
Jun 12, 2023
Messages
1
City
Tennessee
Vehicle Year
03
Transmission
Automatic
I’ve been having an issue where my truck dies over night. Went got the battery charged then I went and got it tested the battery alternator ect were all good. car battery drainage issue didn’t stop, and I’ve made some progress. I went around my truck, checking for anything, that could be causing the problem. And I found several fuses that were draining my battery. I took them out to not drain my battery. It turned out to be the Ac Clutch Solenoid, PCM Memory, Cigar Lighter, Data Link Connector (DLC), Battery Saver Relay, Auxiliary Relay Box, Restraint Central Module (RCM), Generic Electroic Module (GEM), Instrument Cluster and my radio fuse. I’m not sure how to fix them and put the so they don’t drain my battery when I put the fuse back.
any advice would help.
 
Look for chaffed wires to start with. A wiring schematic would help greatly in chasing down the wires and what shares what as far as junctions and connectors. A proper troubleshooting manual for your year of truck would be best since it will tell you what the voltages should be at the components, what colors the wires are, and what pin/socket they are in the connectors.
 
I had the same problem with my 2003. The clock in the radio was one source. Loose connections on the cruise control were another.
 
Welcome to TRS :)

Just a heads up on "battery tests" at shops, do it yourself

2003 Ranger is 20 years old
Batteries last an average of 5 years, so you should just be getting a new battery, last one was put in 5 years ago, so heads up

After driving home, so battery is charged up, unhook one battery cable from battery, either one, doesn't matter
Next morning hook it back up and start engine, if engine cranks slowly or not at all, replace battery, for sure, its self draining, this is how a battery dies, an internal short so it drains itself

Most of the listed "fuses" SHOULD drain the battery with key off doors closed
But only for 20-30 minutes until GEM goes to sleep and shuts off Battery saver relay

Computer(PCM) and radio memory is always "on" and keyless entry(fobs) is also always on
But these are a minimal draw, good battery would last 6-8 months before a "no start" condition

Cigar lighter and DLC are same fuse and have 12volts all the time, so do you have a phone charger or similar device plugged into the cigar lighter or AUX port?
If so unplug it when not in the vehicle, these draw power whether in use or not
DLC is OBD2 port under dash, it will not be a drain unless you have an OBD2 reader plugged in to it
 
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