I have a 1994 Ford Explorer Eddie Bauer 4x4. I have a problem with something draining the battery. I did a bunch of research on how to do a parasitic battery draw test in order to figure out what's causing drain on my battery. Long story short, I tracked down the problem and it's my CD player causing the battery drain.

The wiring to the CD player has two plugs; one is a plug for the factory amplifier (black plug on the right) and the other plug (grey plug on the left) is the normal wiring for the CD player. When I unplug the amplifier, I still have a drain. But when I unplug the other plug (grey plug), the drain goes away. So I took a test light and probed the grey plug (with vehicle off) and found one wire that has power to it. I'm not sure if it's supposed to have power with the vehicle off or not. I assume it would need some amount of power for the station memory settings.

But this is where I get lost and where I need your help since I'm not that good with electrical stuff. How do I find what is causing the drain in this plug wiring? Is it in the CD player itself or a bad ground in the wiring somewhere? What am I looking for? What do I do from here? Can the internals of the CD player be bad and cause this? Or is it in the wiring? Thanks for the help...

 

What method did you use to determine the CD player was the source of the drain? Did you measure the current draw, or just voltage? The reason I ask is because, exactly as you suspect, there will need to be some current draw to retain preset memories and the clock time. But that current draw should be minimal, on the order of a few milliamps.

Did you check all circuits for a drain, or stop checking as soon as you found one that appeared to be drawing current?

-Rod

 

The first method I used to find the problem was to use a test light. I tested every single fuse and circuit until I found the circuit with the problem. It just so happened that it was the very last fuse/circuit I tested when I found it. Once I found it, I referred to my Haynes repair manual to figure out what components were on that circuit. Then I started unplugging those components (turn signal, wiper, high/low beam switch; headlight switch, window switches, instrument cluster) to see if I could isolate what was causing the electrical draw. But after unplugging everything, I still had an electrical draw. So I got on YouTube and watched a video on how to do the same test, but with a multimeter. The video explained how to test for amps; specifically milliamps. So then I went back out and did this test. I had a 3.43 amp drain and when I unplugged the CD player, the electrical drain disappeared and the meter read .01. The video stated that anything that has 50 milliamps or less is ok. Anything more than that then there’s a problem and something’s draining the battery.

So now that I’ve found where the electrical draw is coming from, now I need help figuring out what is causing the draw. Could the internals of the CD player be malfunctioning and causing this (the CD player works fine), or is there some wiring hooked up incorrectly? Not sure what to look for and this is where I need some advice.

 

If that was truly 3.43 amps, not milliamps, that you measured when the CD player was connected but powered off, that's an issue.

I would start by disconnecting, one at a time, the power wires for the aftermarket deck. See if one of those power wires causes the high current draw to go away. I'd suggest starting with the blue power antenna/remote wire.

-Rod

 

I believe I misspoke, let me clarify. I had it on the milliamp setting. Take a look at the picture; this is the setting I had it on.

 

Okay, in that setting if you read 3.43 that would be in milliamps (mA), well under the acceptable 50 mA (or 70 mA, depending on what manual you look at).

Have you tried leaving this suspect fuse out and the Explorer sit overnight (or however long you have in the past) to see if the battery still drains with that fuse removed.

-Rod

 

Have you had your battery checked to make sure its not bad? Take off your hot wire and check there and see what your total draw is. Put you battery on a slow (1-2 amp) overnight charge and check your voltage. If you can leave it for a day or two and check it again or take it to a parts store that can do a battery test. Just because it works doesn't mean its working well.

 

Rod--No I haven't left the fuse out. It takes a few days before it goes dead; 3-4 at minimum. I can leave the fuse out and let it set and see what happens.

So you don't think it's the CD player is killing the battery? When I unplugged it, the MA reading goes to .01 (fuse is still installed in the fuse panel). Doesn't that indicate the CD player is the issue?

I just got done doing an intense wiring analysis of the wiring of the Explorer, the wiring I have spliced into the adapter/connector plug that plugs to the factory plug, and the wiring of the CD player and how they're all connected together. I also used a wiring color identification chart someone posted online for a 94 Explorer and a wiring diagram for the CD player. Long story short, I'm suspicious of the ground wire. Let me explain...

In the factory Explorer wiring there is a solid black wire and according to the wiring color identification chart info I found online it states it goes to ground. However, the plug that connects to this factory plug is missing the pin & wiring in this spot. So this wire isn't connected to anything.

There is also a black w/green striped factory wire and I have no idea what this wire is for because according to the wiring color identification chart info I found online it doesn't identify this wire; doesn't even list it. I have this wire connected to the ground wire into the CD player.

My question is: if the ground wire isn't connected correctly, would this cause a power draw? Or would the CD player not work at all? This is the only possible conflict I can find in the wiring setup.

Spaznaut--The battery is only a few months old, but I can test it to rule it out.

 

If you did not have a good ground to the radio/amplifier, the device would not work or you would have a lot of noise over the speakers. Also, as you mentioned previously, up to 50 mA draw is acceptable for keeping the electronics "alive" in standby mode. I've also seen manuals that state up to 70 mA. You said that you measured 3.43 mA draw from the CD player/amplifier that dropped to 0.01 mA when disconnected. Dropping to 0.01 mA does indicate that the CD player is drawing current, but the amount of current is almost 15 times lower than what's acceptable. If you have a 45 Ah battery (which would be a small car battery), that draw would take conceptually well over a year and a half to run a healthy, charged battery dead. That amount of current draw is not the reason your battery dies in 3-4 days, if the battery and connections are good.

Since your meter does have a 10A scale, try removing a battery cable and inserting the meter on the 10A scale in series between the battery and the cable. You may want to start with the test light also in series to limit the in-rush current draw, then short the meter around the test light. What current draw do you measure this way? What does the draw drop to when the fuse for the CD player is removed?

-Rod

 

Rod, I'm not that great with electrical so I'm trying to follow your instructions, but I'm a little confused and need some clarification.

So I put one probe of the meter on the negative battery post and the other probe on the negative battery cable, correct? But at the same time (before I hook up the meter) you want me to connect a test light in the same manner; clip one end to the post and touch the test light to the cable, correct? Now when you said to "short the meter around the test light"....how do I do this? If both the probes of the meter are already touching the battery post and cable, how do I "short the meter"? I can post the readings once I know how to short the meter around the test light...

 

Sorry, I've been on vacation for the last week.

Yeah, so start by using the test light in series between the battery post and the battery cable. Leave that connected until the test light gets as dim as it's going to get. Here's where you'll need a buddy to help you. Then, with the test light still connected, install the multimeter in the DC mA setting in parallel with the test light. Once the multimeter is connected, then remove the test light.

The purpose of this is to reduce the inrush current of the system via the test light and get the system current draw to steady state before connecting the multimeter since the inrush current draw could blow the fuse within the multimeter which is fused at only 200mA.

Also, I just noticed that in your image of the multimeter you have the red lead in the position for measuring current using the 10A setting, but you have the meter set to DC mA. For measuring mA of current, the red lead should be connected to the terminal on the right side of the meter. Which position did you have the red probe when you measured only 3.43 mA draw?

-Rod

 

Thanks for the explanation of using the test light and multimeter. Makes sense.

Regarding the red lead positioning....I used it in the position you see in the picture. Since I'm not very knowledgeable about electricity, I watched a video on how to do this (Eric The Car Guy) and he said to switch the red lead to this position. However, now that I think about it and after your comment, I think he said to put the setting on the yellow 10a circle. When I initially set it in this position, the only difference I noticed between the yellow 10a setting and the blue mA setting was the decimal position in the display. The reading was still the same in both positions, only on the 10a setting it read .343 instead of 3.43. And since I'm reading mA, I thought it made more logical sense to put it on the mA setting. But as you can tell, this should tell you how uneducated I am about electricity and anything related to it, such as multimeters...LOL. This is why I am on here asking for help, which is greatly appreciated.

So should I have the dial on the yellow 10a setting or does it make a difference? If I understand you correctly, if I'm reading mA, then I need to have the red lead on the right side plug-in and the dial on the blue mA setting, correct???

I haven't worked on the Explorer in about a week nor have I been driving it last week. Someone mentioned to let it set without the CD player hooked up and see if the battery still goes dead. So that's what I'm doing. I might test the battery tomorrow and see if it's still alive.

So in the video I watched, he said 50 mA or below is fine. What does a 50 mA reading look like on my multimeter? .50, .050, 50 ????

 

Well, when reading 0.343 with the probe in the left spot and the dial on the yellow 10A setting, that would equate to 343 mA. Your right "mA" terminal is fused at 200 mA, so running 343 mA through that setting would likely blow the fuse. But this is where things get a bit confusing for me because 0.343 in the 10A setting is not equal to 3.43 in the mA setting. So I would recommend leaving your probe in the left position and only using the 10A yellow setting on the dial. Doing this should also eliminate the need to use the parallel test light trick to address in rush current.

A 50 mA draw on the 10A setting with the red probe in the left terminal should yield a reading on the display of 0.050 A. I would not get concerned unless the current draw once everything is in standby (around 45 minutes after closing the door) is quite a bit more than 70 mA.

-Rod

 

Rod--Thanks for that explanation. That helps a lot.

Ok so I had planned on working on this issue today, but I never got the chance to because I spent all day installing my lift kit in my 78 F150 Super Cab. And now that it's 100*+ outside, I'm done for the day.

However, I haven't driven the Explorer for a week and I've had the CD Player unplugged all week long also. I just went out and put the multimeter on the battery and I have a full charged battery. So without doing anymore mA testing, I just verified the CD player is killing the battery. So now I just have to figure out if the CD player wiring is spliced correctly or if the internals of the CD player are messed up.....correct???? Your thoughts???

 

Did you try starting the Explorer to make sure you weren't just measuring a surface charge, but the battery actually has very little capacity? A multimeter, by design, will provide an extremely small load on the battery.

-Rod