Steve777

Let my 87 Runner sit for a couple of weeks while I got to the clutch master cylinder replacement. Clutch MC replacement was a snap, but found the battery dead when I went to start it. It's a fairly new battery (< 1yr) and has been fine sitting for far longer periods before. So I put a charger on the battery, and started looking for current leaks. I found ~70-80ma draw on the battery even with everything off (this with a recharged battery). Did the standard thing of pulling fuses to find the leaking circuit. Well, it doesn't seem to be connected to any fuse??? No change in leak current with any fuse in the foot well fuse box, and no change in current with any fuse in the box on the passenger side box in the engine compartment (well I did not pull the 80A one as it didn't want to come out and I didn't have a replacement handy). I did try disconnecting each of the wires at the + battery terminal. All the current leak is in the smaller wire there, which goes to that fuse/relay box in the engine compartment, on the pass side fender. Must be one of the circuits that tie in right to that 80A fuse. My question for those who are more familiar with the wiring of these trucks is what circuits go right into that fender fuse/relay box that might be at fault here? Something that does not get fused by one of the smaller fuses or the 30A or 40A fuse in there. Or are there more fuses somewhere I've missed? Any ideas?

Steve777

Let my 87 Runner sit for a couple of weeks while I got to the clutch master cylinder replacement. Clutch MC replacement was a snap, but found the battery dead when I went to start it. It's a fairly new battery (< 1yr) and has been fine sitting for far longer periods before. So I put a charger on the battery, and started looking for current leaks. I found ~70-80ma draw on the battery even with everything off (this with a recharged battery). Did the standard thing of pulling fuses to find the leaking circuit. Well, it doesn't seem to be connected to any fuse??? No change in leak current with any fuse in the foot well fuse box, and no change in current with any fuse in the box on the passenger side box in the engine compartment (well I did not pull the 80A one as it didn't want to come out and I didn't have a replacement handy). I did try disconnecting each of the wires at the + battery terminal. All the current leak is in the smaller wire there, which goes to that fuse/relay box in the engine compartment, on the pass side fender. Must be one of the circuits that tie in right to that 80A fuse. My question for those who are more familiar with the wiring of these trucks is what circuits go right into that fender fuse/relay box that might be at fault here? Something that does not get fused by one of the smaller fuses or the 30A or 40A fuse in there. Or are there more fuses somewhere I've missed? Any ideas?

Steve777

Opps, sorry for that dup post, not sure how it happened... Anyhow a bit more info. Seems the current draw varies some. It was 100-200ma then a few hours later, after starting the engine and checking the battery voltage with the alt turning (14.1v) the current draw with everything off went up to 3.1A Still not tied to any fuse I have pulled. SO I am thinking it must be either a leak in the alt or the starter circuits, as those are the two that do not go through one of the smaller fuses. Any other ideas of places to check???

TNRabbit

Are there any aftermarket stereo, lights, or trailer kit wired in?

Steve777

Had thought about the aftermarket radio (and some of the other hacks on this rig), so I had disconnected them; unfortunately no diff.

But I found the problem. It was the alternator. When I disconnected the big wire the current drain disappeared, very repeatable, touch the wire back to the post, current leak comes back, take it off it goes away.

Had the alt tested, and it failed. Put in a rebuilt one and things are back to normal. Actually better than normal, as this gave me an excuse to pull and clean up a bunch of the lousy wiring the the PO had done.