Hello All,
I'm putting this thread here both to ask for advice/opinions and to update in case anyone else runs into this.


Issues:

1. Headlight Bulb Connector Broken - need to replace... source?
2. Intermittent issue with Speedometer reading zero - when this occurs, VSC/Trac/ABS lighs are on... assuming this is a wiring issue with one of the wheels VSS
3. When the Speedometer doesn't work, and the lights are on, the gas gauge fluctuates wildly
4. Constant Parasitic draw on the battery... runs the battery to completely dead in a week from fully charged. Yes, brand new battery. Yes, I've tried multiple brand new batteries.

Ideas:

1. I am just not sure where to source the headlight connector - I assume any headlight connector of the appropriate bulb type will work?
2. I think the Speedometer and Gas gauge issues are related, so I suspect its not actually at any wheel, but rather in some sort of bulk harness that runs from the rear of the vehicle. The most likely issue is that mice/squirrels/rabbits have chewed up some wiring, but ideas of where to look would be helpful.
3. I don't suspect its the issue with the wiring under the intake manifold as others have reported - even when I am experiencing ALL of the electrical issues, the truck runs great and shifts into all gears as expected.

I'm open to any advice or assistance as to where to start looking. I need to do the draw diagnosis first as I suspect that will lead me in the right direction as to the shorting/grounding issues as well. My order of attack will be something like:

1. Find and repair the draw issue
2. Repair the headlight socket (this may be the draw issue... who knows)
3. Look for Common grounds between the VSS system and the fuel level sensor
4. Look for common pathways between the VSS system and the fuel level sensor
5. Repair any shorted or chewed wires with a soldier, heat shrink, high grade tape approach in a last ditch sledgehammer attack on this.

I know my truck has quite a few miles (256,000!) and has some rust issues (mostly just the lower radiator support... Thanks, New England) but its my hunting/fishing/overlanding/towing rig and I still need her for a couple more years before I replace it.

I know you folks like pictures, so here she is... one dead 180lb deer, 256,000 hard miles towing heavy enough to require an electronic brake controller before I owned it, and lots of rough Maine roads, high way miles through mountain ranges, and light duty towing later (including a fun beach dune jumping trip right after I got the FJ Coils and 5100's installed at 190,000 miles.)

Hey just bought an 05 4runner sport last week now mine is having same electrical issues as yours. All lights come on and ac blows ridiculously hard. Super intermittent issue and yeah it doesn't seem to effect the drive but maybe it would if you happened to already be using 4wd or DAC when this occurred something could potentially go wrong. At first I thought loose battery connections but those were tight. Please let me know if you ever figured anything out on this. Super upset I bought this car and week later all these issues

So sorry to hear you're having issues already. I haven't had a chance to dig into mine yet - crazy year, new job, building a motorcycle.

That said, your AC coming on full blast would indicate something larger. I know you checked battery connections - did you test the battery voltage with the car running? Also, check resistance across the battery cables, but specifically the ground. Does it tend to happen to you more when it's wet or very humid out?

Mine is a v8 so it's full time 4wd. My issue hasn't reappeared, but it still kills a battery in 3 days. Just need to prioritize finding my draw.

Sounds like the electrical draw might be the overall issue.

I suggest searching youtube for how to connect a test light or volt meter to your battery to check for a draw. I can never remember this for some reason. basically pull of negative terminal ad connect device between post and ground cable.

then pull fuses until the draw or test light go out.

This will tell you what circuit you are dealing with.

Related to electrical draw, are there circuits that aren't fuse protected? Eg. alternator/starter? I had some smoke come from my engine bay and it smelled electrical, about 30 minutes later my battery was dead. Its a 2006 V6, stock configuration, 187K miles. Only mechanical problem it has is a valve cover oil leak on the passenger side that I haven't gotten too. I was hoping it was just that but I don't see any oil hitting the exhaust manifold and it wouldn't explain the battery drain. I'm getting a multimeter today to see how bad the electrical short is, but again I was just curious if there are any high amp draw circuits I should look at first! Thanks.

So, finally able to get an update on this:

All of my electrical issues are related to an intermittently failing alternator, that ultimately failed. The bearing in it completely seized.

I've moved on to other projects, so as much as I love my 4runner, its time for it to move on. Going to have it towed to the shop since winter wont let go here and have them replace the alternator, then throw it up for sale.

I am having these exact issues with my 05 sport. I bought it just a few weeks ago and every so often the dash lights up and the a/c turns on full blast and I cannot find the issue or anyone else who has had a similar issue. Did you ever find a fix for this? I dont have the money to have someone diagnose it.

Having same issue with my 3rd Gen, let me know if anything works, I am at my wits end!

Have your alternator and battery tested, strange things can happen if either are going bad or are bad!