Battery drain on MAXI12 Fuse circuit..?

[MAXX RS4]

Well i found out where the extra drain was coming from. It's on the maxi12 circuit. All I know is that its teh HD LPS which controls Exterior Lamps, I/P Fuse Panel.

So now, where do I got from here? How do I narrow this down some more?

 

[MAXX RS4]

Since the I/P Fuse panel was part of this circuit, I went and pulled every single fuse and circuit breaker out and checked the drain. It was still at 2.28.

So now what's left on the circuit to check is the "Exterior Lamps." How do I go about checking this out and where should I look?

I'm in desperate need of help here!

 

[Dano]

You need SNAKEYE on this one. He's the Electrical Engineer ...

 

[MAXX RS4]

You need SNAKEYE on this one. He's the Electrical Engineer ...

Right-o. I've been waiting for him to spot this.. Maybe I'll shoot him a pm if he doesnt respond in a day or two.

 

[b dub]

You need SNAKEYE on this one. He's the Electrical Engineer ...

snakeye ftw

 

[SNAKEYE]

Okay, here I am!

I just took a quick look through the wiring diagrams and have concluded that this could take a little more doing than I feel up to this evening.

I take it that you pulled the MAXI12 50A fuse in the engine compartment power distribution center and that stopped the drain. Am I correct??????

What is more than a bit bothering is that you indicate that you pulled all of the I/P fuses (many of which are fed by the MAXI12 fuse) and still had a 2.28-amp drain. Somehow something is being missed.

Tomorrow I will printout all of the related wiring diagrams and track down the I/P fuse circuits that could be involved. I already have seen that the anti-theft and remote keyless entry circuit are fed by that fuse.

Until tomorrow.

 

[b dub]

snakeye shoots, he scores!!!

 

[MAXX RS4]

Okay, here I am!

I just took a quick look through the wiring diagrams and have concluded that this could take a little more doing than I feel up to this evening.

I take it that you pulled the MAXI12 50A fuse in the engine compartment power distribution center and that stopped the drain. Am I correct??????

What is more than a bit bothering is that you indicate that you pulled all of the I/P fuses (many of which are fed by the MAXI12 fuse) and still had a 2.28-amp drain. Somehow something is being missed.

Tomorrow I will printout all of the related wiring diagrams and track down the I/P fuse circuits that could be involved. I already have seen that the anti-theft and remote keyless entry circuit are fed by that fuse.

Until tomorrow.

Thanks a ton snakeye!
Yea, pulled the 50A fuse and the drain stopped. I pulled every single fuse from the I/P and drain was still there..

Until tomorrow, thanks!

 

[SNAKEYE]

MAXX RS4:

Q1 - Is your GT a coupe or convertible?

Q2 - Does it have remote/keyless entry?

EDITED 1:15 PM EST

Answers to the above aren't really all that specifically relavent as each have basically the same wiring and/or functions.

There are four (4) I/P fuses and one circuit breaker that are fed by the MAXI fuse (50-amp) known as HD LPS:
Fuse #4 @ 10-amps supplies the Air Bag Diagnostic Monitor
Fuse #5 @ 15-amps supplies the Main Light Switch
Fuse #8 @ 10-amps supplies Data Link; Main Light Switch; Clock; Instrument Cluster; Radio; Remote/Keyless Entry Module; Courtesy Lights; Anti-Theft Module; Vanity Lights; Map/Reading/Dome Lights; Glove Compartment; Engine Compartment; Luggage (Trunk) Compartment; and probably some others that I overlooked!
Fuse #16 @ 20-amps supplies the Anti-Theft Module/Controller, and the Multi-Function Switch.
Circuit Breaker #12 @ 20-amps supplies the Remote/Keyless Entry; Window Switches; and Trunk Latch Release

I can not explain how a drain of 2.28-amps can occur with ALL of these unplugged as these devices are in the branch circuits off of the HD LPS MAXI fuse. If ALL of these devices are removed simultaneously ALL circuits branching from the HD LPS MAXI fuse are disconnected and no current can flow through the HD LPS MAXI fuse. The only things protected by the above devices that draw current continuously are the keyless /remote entry and anti-theft circuits. Under normal operation these should not draw anything like 2+ amps.

There are four (4) lighting devices controlled by remote switches fed by Fuse #8 that are most suspect to me (*two of which I believe I mentioned before): *engine compartment (if so equipped), vanity mirrors (on the sunvisors), glove compartment, and *luggage (trunk) compartment.
These are, for the most part, not normally very visible in that they are covered and ambient light pretty much obscures them. In the cases of the engine, trunk, and glove compartments, a loose mounting screw could allow the switches to be closed when the hood, trunk, or glove compartment door are in the closed positions. A faulty hinge on a vanity mirror might allow the switch to stay closed even though the mirror door has been closed. The dim light those things provide isn’t readily visible with the mirror door closed, especially in daylight conditions.

If I get a chance this evening I’ll put an ammeter in my battery negative cable and see what kind of drain I get with the car locked up tight, and then with each of these things (not the engine compartment because the ‘97’s don’t have it) turned on separately. Drat! come to think of it, I don’t have a bulb in the trunk compartment’s socket. I got the car without it and never bothered to replace it. I may have a spare bulb around somewhere that I can stick in.

Unless there are after-market electrical modifications on the car that might be connected to the HD LPS MAXI fuse circuit that you haven’t mentioned, you need to specifically eliminate the above four devices by whatever methods necessary to assure that they are not the culprits.

 

[MAXX RS4]

Wow, thank you for the effort youre puting to this.

The only modifications that *I've done to my car are taking out the sequential tail-lights and modifying the blinker module to control blink speed, replaced the headunit, and wired in a powersupply to a radar detector through the center console cigarette lighter.

During the testing, however, I disconnected the radar and removed the head unit.

This weekend I'll have to make yet another trip home from school to check all those possible areas of fault.

*Though those are the only modifications I've done, there's no telling what the previous owner (dumbass) has done that I dont know about. I once found a live wire running from the positive battery post through my car ending under my rear seat - attatched to nothing! it shorted when I was doing a thorough cleaning of the interior and it nearly set me and my car on fire..

 

[SNAKEYE]

Okay, here what I found battery-drainwise on my Cobra.

First, my 1997 Cobra convertible has neither a stock engine compartment nor a glovebox light!

Second, the following readings were taken with the key out of the ignition switch -
With everything shutdown: 77 milliamps.
With (1) vanity lamp on: 259 milliamps.
With (2) vanity lamps on: 454 milliamps.
With the driver’s door open: 1.5 amps (two lights up behind the
inside rearview mirror).
With the trunk open: 977 milliamps.

Third, with the key in the accessory position –
Digital clock display only: 498 milliamps (compares to 77 milliamps with
everything shutdown)
Digital clock and FM radio at minimum volume: 1.180 amps.
Digital clock and CD player at minimum volume: 2.022 amps.

What does it all mean? I don’t really now, except that nothing compares or adds up to 2.28 amps. Some digging into the GT needs to be done to root out the source of the drain.

 

[MAXX RS4]

OK. Thanks a ton, once again.

Maybe I'm somehow testing this completely wrong and don't know it.

Here's what I do:

I make sure everything is off and no doors are open etc. I then disconnect the bulb to the hood so it doesnt do anything..

I disconnect the negitive battery cable. I take the voltmeter and put one probe on the negitive post and the other probe on the connector. It's set to amps.

One thing my dad mentioned to me while I talked to him today was in regard to the voltmeter. It's a craftsmen that has two different connections for the positive probe. One side is fused and the other is not. He said something along the lines of one for a setup that uses drain and the other side is for other tests.. I don't think he was too sure himself. But he said the fuses were blown so he couldnt check for me.. Is this something I should note?

 

[SNAKEYE]

Your test method is correct.

Your Craftsman meter sound alot like my Radio Shack. The red lead needs to be plugged into a low amperage socket (0-400 milliamps), which is fused, or a high amperage socket (10 amps max.) that is not fused. I believe using the high amperage socket is your best betf or a couple of reasons. First, the low amperage section won't work with a blown fuse, and second, most of the currents you are trying to monitor are larger than 400 ma anyway. If it has an AUTO range setting, use it. The decimel point location will be automatically positioned.
If you have an owner's manual consult it for I/P fuse numbers, and be careful to pull the correct fuse as the numbering on the fuse block can be misleading.
Your reported observations still have me scratching my head!

 

[MAXX RS4]

Your test method is correct.

Your Craftsman meter sound alot like my Radio Shack. The red lead needs to be plugged into a low amperage socket (0-400 milliamps), which is fused, or a high amperage socket (10 amps max.) that is not fused. I believe using the high amperage socket is your best betf or a couple of reasons. First, the low amperage section won't work with a blown fuse, and second, most of the currents you are trying to monitor are larger than 400 ma anyway. If it has an AUTO range setting, use it. The decimel point location will be automatically positioned.
If you have an owner's manual consult it for I/P fuse numbers, and be careful to pull the correct fuse as the numbering on the fuse block can be misleading.
Your reported observations still have me scratching my head!

But here's another thing. When I pulled every fuse (all at the same time - the box was empty!) out of the box under the dash, shouldn't the reading have dropped? What would something like that indicate? I dont see how I'll be able to find a faulty light switch or a closed circuit somewhere if the drain doesn't go away when all the fuses are pulled out.

 

[SNAKEYE]

But here's another thing. When I pulled every fuse (all at the same time - the box was empty!) out of the box under the dash, shouldn't the reading have dropped? What would something like that indicate? I dont see how I'll be able to find a faulty light switch or a closed circuit somewhere if the drain doesn't go away when all the fuses are pulled out.

Yes. That, my boy, is what has me scratching my head! It wasn't absolutely clear to me that you had removed them one at a time and left them out as you went along removing additional fuses. Now it is.
What I have indicated with the fuse and circuit breaker numbers are all of the circuits fed by the MAXI fuse HD LPS. If they are pulled there is nothing left connected downstream from the MAXI fuse, so there can be no drain.
That's why I mentioned the possibility of after-market stuff. Or there is something else going on!
As part of your further endeavors try this: after pulling the #4, 5, 8 and 16 fuses, and the #12 circuit breaker, IF YOU STILL HAVE THE DRAIN have someone pullout and pushin the HD LPS MAXI fuse while you sit quietly in the car listening. Perhaps you can hear something change tone, like a CD drive spinning up, or something, and then pinpoint where the sound is coming from and find the offending device.
This would be a whole lot easier in person! This is almost like giving instructions to the Mars Rover - it takes so long to communicate findings and try to deduce the meaning thereof. Hands-on is infinitely easier.
Good luck.
PS - You might stand quietly outside/around the car and listen for changes of sound as the MAXI fuse is pulled/pushed too.

 

[MAXX RS4]

Is there a possibility that there is a short somewhere on the way to HD LPS circuits?

Does the 50A fuse go to anything else but the I/P's? HD LPS - doesnt that mean exterior lights?

 

[SNAKEYE]

Is there a possibility that there is a short somewhere on the way to HD LPS circuits?

Does the 50A fuse go to anything else but the I/P's? HD LPS - doesnt that mean exterior lights?

A short circuit (which literally means a ‘short’ path to ground!) would be much, much more than a 2.28-amp drain, along with smoke and fire as the wires supplying the short burned up!

"HD LPS" stands for HeaD LamPS. Other exterior lights (sidemarker, parking, brakes) are on another circuit.

Yes, the 50A fuse also serves the main (as in head) light switch which when in the off (pushed-in) position disconnects everything downstream.

For the sake of discussion let's say that the particular contacts within the headlight switch that are supposed to be disconnect when in the off position actually remained in contact (? something broke internal to the headlight switch), then power would continue on downstream to the multi-function switch, where it would (as is normal) be distributed, as determined by the position of the multi-function switch’s stalk, to the low or high beam elements of the headlights. All of which means the headlights would never turn off.

Try doing this: with the battery ground connected and everything in the car turned off (doors closed also), pull the HD LPS fuse and stick your ammeter’s probes into the contacts where the fuse was. Do you get any indication of current flow? 2.28-amps? If not, how much? What I am looking for here is a direct reading on the HD LPS circuit instead of measuring the total drain in the negative battery circuit. There may something (like a relay) that gets its control power from the HD LPS circuit BUT gets the power it controls (the bulk of which makes up the 2.28-amps in the battery negative circuit) from yet another MAXI fuse! Of course, while monitoring the negative battery drain you could also pull other MAXI fuse while the HD LPS MAXI fuse is installed.

Nasty business, what!?

Get back when you can on the above.

 

[MAXX RS4]

Won't be able to test anything until Monday night, then I'll be gone and away from my car for two weeks.

I just dont understand how I'll be able to find a light thats stuck closed somewhere if the drain doesnt go away when all the I/P fuses are pulled at once. Where else could the drain be coming from? It boggles me.

 

[SNAKEYE]

Won't be able to test anything until Monday night, then I'll be gone and away from my car for two weeks.

I just dont understand how I'll be able to find a light thats stuck closed somewhere if the drain doesnt go away when all the I/P fuses are pulled at once. Where else could the drain be coming from? It boggles me.

Like I said before, it's got me scratching my head too. It is probably not a switch or its associated light, or you'd see it. A 1-amp drain by a light bulb, like the trunk lamp, is very visible, especially in the dark! A 2&1/4-amp lamp would make lots o' light! You've covered all of the possible hidden lights. It must be something electronic (anti-theft/keyless remote/some dumb relay). As for how can the drain continue with all of the I/P fuses pulled, it is possible because (believe it or not) not everything is protected by an I/P fuse.
Disconnect the battery while you're gone if you don't turn up a solution before you go away (some place warm and dry, hopefully)

What you may have to do is get it to a professional for some hands-on therapy.

 

[MAXX RS4]

Like I said before, it's got me scratching my head too. It is probably not a switch or its associated light, or you'd see it. A 1-amp drain by a light bulb, like the trunk lamp, is very visible, especially in the dark! A 2&1/4-amp lamp would make lots o' light! You've covered all of the possible hidden lights. It must be something electronic (anti-theft/keyless remote/some dumb relay). As for how can the drain continue with all of the I/P fuses pulled, it is possible because (believe it or not) not everything is protected by an I/P fuse.
Disconnect the battery while you're gone if you don't turn up a solution before you go away (some place warm and dry, hopefully)

What you may have to do is get it to a professional for some hands-on therapy.

Yea, while I'm at school (my car stays at home :whine: ) I leave the battery disconnected. Monday night before I leave I'll give it my last try to try and find something. How would I check to see if it was something not on the fuses? If it was the anti-theft/keyless remote/some relay - how would I go about checking it?

I'm trying to avoid taking it somewhere as much as possible. Being at school and unemployed with less than $500 in the bank is real tough.

I'll be headed to jersey and staying with my girlfriend for two weeks. Some place warm and dry? No. Hot and wet? Yes. :banana:
That was crude, but it worked so well. :loser: