Battery Drain -Underhood Fuse
 

I do have a short somewhere that is draining the battery. I connected a multimeter in series with the negative battery post and have a reading of over 200 miliamps. Pulled each fuse in the block inside the car with no change, disconnected the alternator-no change. SBF #4 fuse located in the fuse block under the hood if removed will change the reading. Diagram shows wiring going to the ignition switch. With fuse removed I get a no start or no dash lights which is expected. Anyone have a clue what is connected through this fuse or anyone else had a short at this location? Any help at this time would be appreciated. Thanks

The manuals show that fuse No. 4 supplies the fog light circuit which is quite complicated. A drain of 200 milli amps is hard to fathom. You must accept some residual standing current to maintain clock and computer memories. How much does the reading change after removing fuse 4. :confused:

While registering the current drain, try removing the fog light relay and observe results and report back. If the drain changes it will put some of the circuitry out of the suspect area. Damp spider webs or whatever, behind the fog lights are a thought. ;)

No 4 is the fuse located on the fuse block inside the car under the dash panel. The Fuse in question is the SBF No 4 located in the engine compartment fuse panel which when removed will drop the current draw. I am unsure where to start to trace the source of this short.

Fuse SBF 4 (45 Amp.) supplies the ignition switch and everything controlled by the switch. There should be no current in this circuit with the switch off.

How much does the fuse drop the current draw when removed, i.e. what is the static drain when removed.?:confused:

huh?
 

What does SBF mean?

standard blade fuse?

lol or it could also mean:

cronym Definition
SBF Salvo Buon Fine (Italian: reduction in price effects subject to collection)
SBF Scholastic Book Fair
SBF Singapore Bowling Federation
SBF Single Barrier Failure
SBF Single Black Female
SBF Skin Blood Flow
SBF Small Block Ford (automotive engine)
SBF Social Brain Foundation (China)
SBF Société des Bourses Francaises
SBF Support By Fire
SBF Surface Brightness Fluctuation
SBF Swiss Boomerang Federation
SBF Synthetic-Based Drilling Fluid

"Slow Blow Fuse"? ;)

Getting that current to drop out by yanking #4 could only be a "leaky" ignition switch, unless you've got some custom wiring.

Per the service manual, the only place that current travels to from #4 is the ignition switch.

For sport, try pulling #2 (), #3(), and #17 (radio) in the cabin instead of SBF #4, and see if any of these make a difference?

If the numbers don't help... lemme get back to ya.

SBF could mean Sub Board Fuse.;)

However could we keep trying to assist, in which case an answer to my post as above would be productive. :)

I once again pulled all the fuses both at the under the hood location and under the dash. SBF 4 is the only one that drops the currrent. Next I put a ohm meter between the positive battery cable and ground and got a reading but only on the cable that goes to the fuse box. The starter cable reads infinity. Disconnected the alternator again with no change.

Please answer my specific question if you require further comment. :(

Does it have power seat belts? Because in my 92 the power seat belt modual was fried.

i.e. refer: -----

Post No. 1.

SBF #4 fuse located in the fuse block under the hood if removed will change the reading.

“Change”, means there is still a reading as one would expect.

Post No. 2.

You must accept some residual standing current to maintain clock and computer memories. How much does the reading change after removing fuse 4.

Post No. 4.

How much does the fuse drop the current draw when removed, i.e. what is the static drain when removed.?



Alternatively, do you get an absolute zero reading after fuse 4 is removed?:confused:

Trevor, Here is an update. Borrowed another digital meter, was only able to get a reading on the 10 Amp scale. Reading was .350 with the door open and .02 with it closed. I am interpreting that as 20 milliamps which is what it should be. Alternator is putting out about 14.6 volts from memory. Mystery still exists why the battery is draining after a few days. This all started when driving the car, window started to go up slowly, air bag light came on , felt slugish for a few blocks, and it stalled out. With a boost it ran for 40 seconds and battery which was 20 months old quit again. Replaced battery with a new one and something is discharging it. I am really at a loss now what to search for next.

Make sure your door lock/unlock switch is not sticking. This is the switch located by the transmission shifter (right arm). Mine was stuck and was draining my battery between 24-48hrs. TomsSVX changed it out and it has been fine so far (knock on wood). Good luck!

I am sorry I am inclined to give up. It impossible to diagnose an issue properly with so many confusing statements and curious symptoms.:eek:

“Borrowed another digital meter, was only able to get a reading on the 10 Amp scale.”
On the first meter used or the borrowed one? If you can not get a reading on a lower scale, you probably have the plug inserted in the separate socket for the 10 amp range which includes a heavy shunt resistance. If not, the meter is faulty.

I now must assume that with fuse No. 4 in place there is a reading of 200 milli amps, and with the fuse removed 20 milli amps, which means that you are involved with a leakage of 180 milli amps, i.e. provided the .02 amps measured is accurate.

I am unable to understand why the door circuits are being brought into the discussion, as the leak has been shown to be confined to circuits switched by the ignition key switch.

I gather the other strange previous symptoms you now report, have become corrected after the battery was replaced. Please confirm.

There have been several posts reporting a loose ignition switch causing strange faults. Carefully check the switch mounting bolts, connections and associated wiring for faults. Keep the meter in place registering the leakage while pushing stuff around and working the key about in the off position. You should be able to get the meter in a position whereby you can see it through the windscreen.

P.S. Sort the meters out and make sure you are using one which is accurate and is registering on the correct range.