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under dash fuses

9

92tahoexj

NAXJA Forum User
Location
Southwest PA
does anyone know what the "FL/PASS" fuse does? I have a 92' limited and I'm having some electrical issues that keep killing my battery. This was the only fuse that was blown. I've already removed my radio, disconnected my fog lights, backup lights, and custom headlight harness, but my new battery(1 week old) is still dead by morning. Once I jump it, it charges up fine, and if I remove the negative cable it keep running, so I don't think it's the alternator. The only thing that seems to work is disconnecting the battery at night.
 
If you can really remove the negative cable and your vehicle keeps running there is something really weird going on.

That said try this: with the negative cable disconnected remove the positive cable from the battery. Reconnect the negative cable. Connect a 12volt trouble light between the positive battery terminal and the positive cable end.

The draw will be indicated by the brightness of the test light. Pull fuses or disconnect harness connections until the light goes out completely or substantially dims--things like the radio's memory will always cause a minute draw--once you have located the circuit causing the heavy draw you can isolate/repair it.
 
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You've already done it now but it is not recommended to remove battery cables on modern vehicles while running because of the potential of causing voltage spikes and frying delicate electronics.

FL/PASS fuse relates to the action of flipping the lever to momentarily flash the high beam headlights. Not sure how or if this might relate to your problem.
 
Pelican said:
You've already done it now but it is not recommended to remove battery cables on modern vehicles while running because of the potential of causing voltage spikes and frying delicate electronics.

FL/PASS fuse relates to the action of flipping the lever to momentarily flash the high beam headlights. Not sure how or if this might relate to your problem.
Click to expand...

The person I spoke to at kragen told me the remove the negative cable while it was running to check if it was the alternator before I bought a new battery. It's the last time I listen to them I guess.:dunce:
I don't have a trouble light and my volt-meter is broke, so I'm just removing fuses one at a time to try to narrow the problem down. I just replaced my H4's with my old headlights and plugged them back into the factory harness. If that doesn't do anything, then I'm getting closer.
 
I believe you should be able to disconnect your battery while the car is running as the alternator will be able to supply enough electricity to power everything - so the Kragen guy might actually know his stuff :)

I like the idea of the check light above, except I'd use the negative terminal instead of the positive terminal to do the test. Either cable will work as you're checking electrical flow which happens on both, and it's generally good advice to disconnect the negative first (or only as in this case).
 
IMHO. NEVER remove a battery cable while the motor is running. You have a very good chance to kill the alternator, and maybe your PCM. Alternators need at least a small current to work, so with no battery current to excite the magnetic fields, it cannot produce any voltage. This is a carry over from the (VERY) old days when vehicles had generators, not alternators. Those used permanent magnets to produce the electrical field, and if you push started one, you could run it without a battery. That guy at Kragen is an ignorant asshole who doesn't have the vaguest idea what he is talking about.
 
Winterbeater, why don't you tell them how you really feel about it! LMAO!

Kinda reminds me of the ignorant asshole at Bi-Mart that when asked if they sold blackpowder she opened a can of smokeless and said "Yeah, its black."
 
winterbeater said:
That guy at Kragen is ignorant...doesn't have the vaguest idea what he is talking about.
Click to expand...

100% agree-- I'm not sure if he's an A-hole, but he's definitely ignorant. I know on newer "voltage sensing" systems, if you remove the path to ground, you are essentially telling the alternator that the battery is completely dead and, thus asking it to make every bit of electricity it can. This will overheat and kill an alternator as well as any electrical device on the output side of the alt. in short order.

Ford got this one right on the "TFI", post Duraspark ignition OBDl versions of their vehicles-- they had a "shutdown if ground is removed" feature built into their ECU's for this exact scenario.
 
winterbeater said:
IMHO. NEVER remove a battery cable while the motor is running. You have a very good chance to kill the alternator, and maybe your PCM. Alternators need at least a small current to work, so with no battery current to excite the magnetic fields, it cannot produce any voltage. This is a carry over from the (VERY) old days when vehicles had generators, not alternators. Those used permanent magnets to produce the electrical field, and if you push started one, you could run it without a battery. That guy at Kragen is an ignorant asshole who doesn't have the vaguest idea what he is talking about.
Click to expand...


i agree about not disco,ing the neg term while its running but the exciter circuit is only needed breifly at startup to make the alt create voltage
 
ok, so i narrowed down the power draw to the dome light fuse. If I pull the fuse overnight, it doesn't kill the battery. so far, i know this fuse controls dome lights, power door locks and factory alarm. am I missing anything?
 
im probably at least the fifth owner and i havent checked the fuse box out too close.
most likely rewired. ill have to check- now im curious.
 
On the 93, there are at least two fuses for the radio. The main switched power is the no. 2 - 15a fuse. The no. 9 - 10a fuse controls the dome and courtesy lamps and radio memory lead (I didn't realize till recently that my radio will not play without the memory lead connected -- don't know if all HUs are the same.) Power door locks have separate 20a fuse in the no. 13 slot.

Purely a guess, but I'm wondering if the non-operation of the locks and dome light relate to the alarm in this case. You don't say what amp the fuse is for the alarm and I don't find a slot for an alarm fuse in my manual.
 
Pelican said:
On the 93, there are at least two fuses for the radio. The main switched power is the no. 2 - 15a fuse. The no. 9 - 10a fuse controls the dome and courtesy lamps and radio memory lead (I didn't realize till recently that my radio will not play without the memory lead connected -- don't know if all HUs are the same.) Power door locks have separate 20a fuse in the no. 13 slot.

Purely a guess, but I'm wondering if the non-operation of the locks and dome light relate to the alarm in this case. You don't say what amp the fuse is for the alarm and I don't find a slot for an alarm fuse in my manual.
Click to expand...

the alarm doesn't have a seperate fuse as far as i can tell. it is disabled when i pull the dome light(10A) fuse as well as the power locks.
 
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:yelclap:
HOLY CRAP!! I think I might have found it!! After looking at the wiring diagram in my Haynes manual I noticed there was a light in my glove box. I never even knew that.:dunce: One of the screws is missing from the latch. I unplugged the light. Now I'm going to put the dome light fuse back in and see if maybe the light was staying on and killing my battery. It's kind of like checking to see if the refrigerator light stays on when you close the door!:clap:
 
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