Electrical Issue Things to Look for

MattAK

MattAK

New member
Hey all. We're having a strange problem with my previous '01 that I sold to my dad a couple of weeks ago. Here's the story

My 21 year old brother is currently using it and he decided to try and install a sub/amp all by himself last weekend. He has little experience working on cars and didn't disconnect the negative battery terminal before connecting his amp to the positive terminal. In his words "there were a few sparks". He did ground the amp to a bolt in the rear before attempting to connect the positive cable. I'm not sure if he ever was able to get the amp to turn on after connecting it to the HU, it wasn't working by the time I got there. I disconnected the amp positive cable and we left it tucked up out of the way far from the battery. The truck started and ran just fine and did for several days.

Yesterday he went out to drive it and the battery was dead dead. No lights were left on and once it was jump started it seemed to be running fine, no lights or warnings. On the way home he said the HU suddenly decided to reset itself, like it does when it loses power. After letting the truck sit for most of the day the battery was dead again last night.

I'm going to take it to get the battery, alternator, starter, etc. tested and I'll check all the fuses and visible cables and pull the HU to be sure he didn't short something back there. Is there anything else I should be looking for? I'm hoping he just toasted the battery (it's practically brand new too :frusty: ) but any ideas of other things to check as well would be appreciated.

Thanks!
 
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I recently bought a 97 that seemed to have the same problem. At first I thought it just needed a new battery, but when I replaced that the problem continued. There some after market lights and brake assist that had been installed on the vehicle. I took it to a mechanic, spent quite a bit of time (and my money) troubleshooting the problem. He traced it back to back to what he called the main relay box or main junction box. He said the after market parts had been hooked up kind of shady, but even after he disconnected everything there was still a substantial drain on the battery. He suggested that I replace the relay/junction box ($142 part for my model, he says depending on the VIN of your vehicle it can run upwards of $300) and he would then reconnect the aftermarket parts properly.I told him to go ahead and do that. I haven't got the vehicle back yet, so I don't know if that fixed the problem, I will let you know if it works out.

Electrical problems suck, at least for me, because I don't know much about troubleshooting them, or the the general schematics of the 4Runner. In my experience, you can expect to drop an hour or two of labor just on trouble shooting before the actual cost of the repair or replacement job kicks in.

I wish you luck.
 
Thanks! I hate chasing electrical issues too, that's why I was hoping to get some additional ideas before I go over there tonight.
 
First things first. How Old is the battery? They don't last much more than 36-40 months in hot ol' Texas.

A mis-wiring that causes a few sparks should not have killed anything but a properly installed FUSE. Make sure new fuses are wired in Very near the battery. Luck on tests. :cowboy:
 
jgue467 said:
First things first. How Old is the battery? They don't last much more than 36-40 months in hot ol' Texas.

A mis-wiring that causes a few sparks should not have killed anything but a properly installed FUSE. Make sure new fuses are wired in Very near the battery. Luck on tests. :cowboy:
Click to expand...

Yeah the battery is only 4 months old. Interstate from Costco. The amp cable came with it's own fuse and that wasn't blown but I'm not sure when exactly he was sparking stuff. /sigh
 
Maybe the amp is on all the time , try disconnecting the amp completely , charge battery and let it sit unless you have a ammeter and can check what the parasitic draw is.
 
I disconnected the amp from the battery last weekend and it hasn't been re-attached since then. I coiled it back by the brake cylinder away from the battery.
 
higgy said:
Did you disconnect the trigger wire to the amp?
Click to expand...

It wasn't ever hooked up. This particular HU has one blue/white remote wire and one special port that seems to be intended for the amp remote wire but needs an adapter that we don't have. The HU wire is currently connected to the power antenna so the amp remote wire wasn't plugged into anything.

My dad charged the battery and when he connected it back up it wasn't starting. On Accessory the lights were ok but everything died when he turned it to run. He disconnected the battery and cleaned the posts with our battery post wire brush cleaner and scraped the connectors as well. They looked ok before, no build up or anything. When he reconnected them it fired right up no problem. He took it to Oreilley's and they tested the batter/starter/alt and said the battery was fine but the starter/alt were erroring at idle (I assume 'cause the alt sucks at putting out power at idle. always has).

I plugged in my Scanguage II to monitor the voltage and ran it through it's paces for half an hour last night. I was getting 14 - 14.2 volts @ 2k rpms for a while. I would see the volts go down as I put a load on the system like turning on the radio, headlights, full blast on the fan, wipers, etc. After about 10 minutes the volts dropped to 13.6-13.8 V. I assume that was after it was done charging the battery?

After I was done testing it while running I turned it off and unplugged the negative terminal and tested the battery level. The dvm was reporting ~13V after just having run. So I plugged the negative terminal back in and we're letting it sit today and I'll go check it tonight to see if there's been an appreciable drain.

My brother explained better what he did to arc it so bad. He couldn't get the positive cable off the battery after loosening it so he was prying on it with some metal pliers. The pliers touched the metal strap holding the battery down and arced, which also singed his arm hairs apparently.
 
Take the truck to the nearest auto parts store (any one that does free battery checks) and get your battery load tested. After ruling that out things get a little more complicated.
 
My first move would be to disconnect -everything- related to the radio installation. It is obviously not a fuse or burned circuit problem since the car starts and everything is working fine once it is started.

In these kind of problems, 99.9% of the time it is related to the newly installed device.

Other clue is that the battery was totally dead, which means that there is pretty much certainly a continuous current drain once the car has stopped.

He may have wired the signal wire to a always on source

Edit: was on mobile, didn't read your other post. Since you disconnected everything already, I really don't know what to say beside ''are you sure''. How long was that head unit intalled before the amp? AFAIK, one short should not kill a battery... if it did, I would have killed a lot. I would give another look, and see around if there is till ''anything'' connected to the new installation, take it all off the car, even better.

There is something draining your battery while the car is off, and it is probably related to something newly installed, hope you find the problem.
 
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diverscale said:
My first move would be to disconnect -everything- related to the radio installation. It is obviously not a fuse or burned circuit problem since the car starts and everything is working fine once it is started.

In these kind of problems, 99.9% of the time it is related to the newly installed device.

Other clue is that the battery was totally dead, which means that there is pretty much certainly a continuous current drain once the car has stopped.

He may have wired the signal wire to a always on source

Edit: was on mobile, didn't read your other post. Since you disconnected everything already, I really don't know what to say beside ''are you sure''. How long was that head unit intalled before the amp? AFAIK, one short should not kill a battery... if it did, I would have killed a lot. I would give another look, and see around if there is till ''anything'' connected to the new installation, take it all off the car, even better.

There is something draining your battery while the car is off, and it is probably related to something newly installed, hope you find the problem.
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I originally put that HU in my Lexus IS300 in 2011. When I traded it in for the 4Runner I moved it over, so the HU has been in there for over three years. Without the amp power connected it's definitely not that. I let it sit all last night and all day today and when I measured the battery with the dvm it read 12.62V and it started right up. I'm not sure if that voltage is normal or not. :shrug: We're going to let it sit overnight tonight and check it again tomorrow. I'm also going to pull the HU to see if he messed anything up when hooking up the amp; I didn't have time tonight or last night to do that.
 
don't know how much power your new system is trying to pull....and maybe not the fix for "this" problem...but maybe you need to think also about the cs144 140 amp alternator swap if your charging system is acting iffy
 
I think you need to hook up an ammeter to see what the draw is on the system, thats what i would do and then depending on draw, start pulling fuses to isolate the circuit.
 
Sounds like the battery went dead, no one ever says "I left the dome light on" or "I had the doors open for 9 hours". Of course you didn't completely check the battery, but it sounds like its OK.
 
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