Oh boy, where to start... committed to an 86 4runner rebuild. Just got done rebuilding all the brakes and LSPV. All's well in the stopping world. Except now, mysteriously the key buzzer has stopped working. Along with that, there is a slow draw on the battery. Enough that the battery is dead come morning. Alternator was tested and is good. Battery replaced and is good. I replaced the ignition lock tumbler a while back, buzzer worked fine after. Everything was fine prior to doing the brakes. Only thing I can figure is when I got up under dash panel to adjust brake pedal throw was that I ˟˟˟˟ed something in the wiring harness. The two big mysteries are the key buzzer not sounding suddenly and the parking brake dash light staying on after the ignition is turned off and key removed. Thoughts? Discussion? Carrying jumper cables and relying on the kindness of strangers is not really an option...

 

Put an ammeter in series with the positive battery cable and pull fuses until you identify the circuit that is drawing current.
That'll get you started.

 

Thanks. That's been the better part of my day. Problem is PO butchered the wiring harness. I've narrowed it down to the fuse box in the engine comp I think. When I pull the positive off that the battery draw stops. But none of the individual fuses seem to replicate that. Also didn't explain the key buzzer or the parking brake light. I hate electrical issues. I got mechanical problems all day. Electricity is like voodoo to me.

 

How big is the parasitic draw on the battery? Put a multi-meter inline with the battery ground, wait a couple of minutes for draw to settle and read the milliamps. Power draw should be under 50 milliamps. This will display as 0.05 amps. My 86 truck is at 0.01 amps.

https://www.bing.com/videos/search?q...tail&FORM=VIRE

My truck is at 0.01 amp.

 

There is a little module up under your drivers side dash for the key buzzer, you probably bumped it when you were in there. As for your current draw, you said parking brake light stays on after you have pulled the key? Clearly whatever circuit that light is connected to is getting power all the time. So yank fuses until that light goes out and then see why that circuit is getting constant power.

 

Millball gave you the crucial first step.
When i got mine one of the first things I did was remove any non-Toyota wiring and solder/shrink tube the harness back together. Most of my harness damage was under the dash on the driver's side. Pulling those lower trim panels is quick and easy, and makes the job a little easier.
I don't see how adjusting the brake pedal would have affected the key buzzer, but that's assuming it's all factory. The connectors lock together and typically can be hard to unplug. But maybe you jostled someone's prior poor wiring repair.

I think a 50 milliamp draw is too high. bitd on these older vehicles we wanted to see less than 30. Modern vehicles have multiple ecu's storing data that need energy even when sitting, but back in the 80's there was a lot less things needing power when inert.

 

Agree on older vehicles as few to draw, but at 50 his battery is safe even with some added draw no matter the vehicle age. A good max value. These old trucks should have well below 30. Mine is 10.

 

Thanks y'all for the suggestions. I'll start chasing things this week. Some things I know the PO did to butcher this harness include:
- Swapping from an automatic to a manual.
- Splicing in an aftermarket stereo.
- Wiring in a "kill switch" on the starter.
- Rewiring a switch for the rear window.

I've already pulled the stereo and will work on rewiring that. I'll post some pix of the rats nest I'm dealing with. I am especially stoked on the fuses that are oversized and/or burnt! 🙄

 

 

About what I figured.
They have stereo wiring kits available that will fix the loom at that location. It'll even have a connector like the oem. You can either source a oem stereo and just plug in, or get an aftermarket unit and an adapter wire that lets you plug the stereo into the loom.
I solder and shrink tubed my repairs, but working under the dash isn't fun, especially the driver's side. I do like the non-insulated crimp connectors. Then you can slide shrink tube over the connector. A lot cleaner(thinner) looking than those blue and red insulated ones typically used, and I think the shrink tubing minimizes wire flexing at the connection.

 

Thanks Jim. I think I'm gonna leave out the stereo all together and get a Bluetooth speaker that connects to the music on my phone. Simple and one less headache. I'll post pix as I go through this mess and clean it up. Ohh the joys of fixing another person's tweaker mess...

 

Ah. Well, even if you don’t use a regular radio it’s a cheap way to terminate all those wires cleanly.

 

Thanks Jim. I'll check it out. I've managed to narrow it down to a few possibilities. Parking brake light and fuel gauge are receiving constant power after the ignition is shut off. The light will go out after you turn on the turn signal for a few seconds. Seems to draw the power down. I pulled every fuse under the dash and in the engine comp and none of them turned off the light. The only way to shut it off is to pull the positive lead to the fuse box in the engine comp. Soooooo, my thought is power is coming from that fuse box but the fuses aren't working. It's then getting routed to the fuse panel on the drivers side wall. I can hear one of the relays clicking as power draws down. I can a also hear an electrical click from what seems to be the wiper motor under the hood. I replaced the ignition bundle with one that I know is good. No change. I suppose I can swap out the two fuse panels... Any thoughts?

 

I think your best bet is to remove everything that was ever added, making sure to repair the factory loom in a way you’ll never doubt. Solder is good, but so is a good cold crimp. Just don’t use those wretched quick-splices. Aftermarket Wiring looks clearly different than the oem. You’ll get good at quickly spotting it.

If tow wiring was ever added I’d remove that, too. They usually made the connection in the left 1/4 panel where the jack is, but sometimes they ran wires to each tail light. Tow wiring has caused more than a few issues.

These vehicles were stolen A LOT Bitd. Consequently, many owners installed alarms of various quality. Some of the lamer ones had the driver hitting the turn signals when starting, or the hi beam switch. So you might have alarm wiring under the dash. I’d remove that, also.

On the positive battery post you’ll have the cable going to the starter, along with a thinner wire(actually a fusible link) that goes to the fuse block sitting just behind the battery. Any other wire(s) are most likely ones added by a previous owner. I’d track that and remove whatever it was powering.
As you undo these add-ones and repair the loom I’m willing to bet most of your issues will resolve themselves. But if they don’t, testing will be a lot easier with them removed from the equation.

 

Thanks Jim for the encouragement! I'm learning more about auto electrical than I ever wanted through this process. Haha! I'll keep ya posted.

 

I totally agree with everything JimKola said. I would like one thing though. if I may.

First, let me give m credentials: I was a Radar Technician my entire working life, first in the Corps, then at a government run Aerostat Site. You can Google that easily enough. I was made the lead Electronics Tech after working there 6 months, and a few years later, a Flight Director, but they still consulted me frequently on things regarding the radar system. My education included a few soldering schools.

I recommend soldering any "broken" wires, ie: wires that have be cut or whatever else was done to remove a electrical system, including wires that have additions into them running anything the Toyota engineers didn't originally include in the vehicle. Soldering should finish with a piece of heat shrink over the solder join, covering all the exposed wiring. Especially wiring in the engine compartment. There, you should use the meltwall, or FIT-300 type, heatshrink. It will protect the solder join as well as if it were covered in insulation from the factory. This type of heatshrink is readily available from Grainger, or McMaster-Carr.
Electrical tape doesn't last anywhere near as long as heatshrink does. Nor does it protect anywhere near as well.

I'm so big on soldering because it nearly duplicates an unbroken length of wire. A crimp is not a bad way, don't get me wrong, I just prefer solder joins as I used them in my radar systems, and they did a very good job for me. Radars in jet fighters get a lot of abuse, so you want a good, lasting, join. Same with the heatshrink.

Also, and I hate to carp on this, but many people ignore the grounds. Check every one you can find. A bad, or dirty, ground can cause all kinds of troubles that can be very difficult to track down. Pay as much attention to the grounds as any other part of an electrical system. They matter just as much as the positive, or "hot", portion of an electrical system.

OK, ok, I'm done. I hope this isn't TLDR...
Pat☺

 

Appreciate the feedback Pat! I've pulled the grounds and wire brushed them all clean on both surfaces. Tightened solid. So at least I know I'm good there. My plan is to definitely solder each joint and shrink wrap. I'll check out the brand you recommended.

 

I do prefer soldering, but I think I’ll get some open barrel splices next time I place an order with EasternBeaver.com
They also sell quality terminals at a very fair price; from the same supplier Toyota uses. But you do need an open barrel crimper. Bomber crimp once you get good at it.

 

A big part of the mystery has been solved! While it doesn't account for all the ˟˟˟˟ery the PO did with the wiring, I found a big part of the mystery power draw. The 3 wires on the connector for the alternator were all worn bare, coated in power steering fluid and oil and subsequently all touching each other.

I only found it because as I was disconnecting and reconnecting the negative cable from the battery I heard a popping/ sizzling sound, look over and see smoke then a little flame! Glad I sorted that out before I came out to find a flaming inferno! I'll keep working on replacing and repairing all the wiring but thank you to all who offered suggestions and pointed me in the right direction! I feel a LOT better now...

 

I found a video on YouTube that explains very similarly the problem I had. Mine was the connection though and not the diode itself.