Interesting Electrical Issues... Long Post w/ Diagram

Bought a totaled 07 Base Single Cab Tacoma off auction in 2020. Not much was done to it, the someone installed fog lights and tapped into the running sidelights on the headlights, typical stuff. - I didn't notice that these fogs were tapped in the harness originally until recently, but makes sense since this is a base model.

Since then, I've slowly just installed accessories, whatever. I'll attach a photo of my wiring diagram at the end of this post. I'll now go into what I have, ordered by install date (oldest to newest) and issues that have come up recently.

• Lightbar with interior OEM switch - installed 2020
• Aftermarket Headlights and fog lights - 2022
  • Daytime running light portion tapped into that same sidelight wire
• Subwoofer with build in amp - 2022
• Ditch lights - 2023
  

Now to what's been going on - I've had all these accessories running together for some time now, no issues at all. About two months ago now my subwoofer randomly would cut off every once and a while and then come back on after a bit. It eventually gave out. I made sure it was getting proper power to the actual system, it was grounded correctly, etc. Once all of that was confirmed, it was then warranty replaced. Got the replacement and it did not work. I didn't care to look more into it at the time, was busy, whatever.

About a week after my ditch lights randomly started cutting off when using them, eventually to where they would not turn on. Well, what do you know, I plug up my subwoofer again and it works fine, no issues. That resolved itself, now my ditch lights do not work.

I just noticed last week that my LED fog lights seem to be lacking power, they're really dim and figured my Amazon special was going bad, whatever, ordered a new pair.

I got my new fogs a couple of days ago and figured I'd start troubleshooting the ditch lights. I check the power where the wiring harness connects to the lights and my multimeter is only reading .8 volts or so. The inline fuse is fine, I tried a new one did not fix it. The relay is fine, swapped it to my LED bar, did not fix it. LED Bar worked with Ditch Lights relay. Weird, contacted CALI Raised and they agreed to send me a new set. (Will update if a new set fixes this, but I doubt it because it seems my issue is elsewhere.)

I stop focusing on that and then go to change my fog lights and what do you know, the new ones do not work. I used some bare wire and connected the fogs straight to my lightbars power and they light up fine. Old pair and new pair.

Tested the battery at Advanced Auto and it's just fine. I can't pinpoint why stuff is randomly falling out and coming back after things worked fine for so long together. Could it maybe be some of the stock fuses? I would assume if let's say a headlight fuse (since the fogs are tapped into the side lights) if it was bad then no lights would work.

Is it maybe to the point where my accessories are drawing too much power? Is that even a thing? Right now, it has a DieHard Silver Battery: 24F Group Size, 650 CCA, 812 CA, 130 Minute Reserve Capacity, For Lower Power Demands.

Alternator? I don't assume this is the case because these things are hardwired to the battery (except the fog lights) and the battery was good on the test. By now it would've sucked the life out of the battery if it's been going bad, no?

I'm not an electrical guy but can work on cars. Hence why I'm just lost. Tried installing all this proper, and I know what every wire does, I just don't know what's up considering it's all worked for so long, no issues.

 

If your battery is starting your truck just fine and not running out of juice over the course of many days, then your battery/alternator are fine. When you flip either one of the switches, do the relays audibly click? If so, everything on the energizing side of the circuit is likely fine, otherwise the problem lies there. And if they do click, and the problem is on the other side. Let’s start there before diving in any deeper.

 

Okay, thought so the same but had people saying the battery and alternator were the cause in person and I couldn't believe it. Thanks for the reassurance. Funny enough the ditch lights relay isn't clicking like my light bar one is. But I can't understand why it works whenever it's swapped and the lightbar is plugged into the relay for the ditch lights. Once I receive the new harness maybe there's an issue past the relay and that was just unlucky.

And maybe this is all a coincidence with the fog lights and the wiring job the previous owner used has just gone bad.

 

Usually when diagnosing, you don’t want to make any changes, because the problem can go away temporarily and you think it’s been fixed when really you’ve (for example) make a bad wiring connection work for a while. But in this case I think you’ve got something pretty basic/fundamental going on like a bad ground, so perhaps you could disconnect everything except one accessory that’s acting up and if it continues to misbehave, start doing some voltage measurements.

The thing to be aware of is that accessories that want to draw some current will have a measurable voltage drop across a resistance (in this case, a bad connection). You can use this fact to find where such bad connections are by using the battery +/- terminals as your reference, and looking for voltage drops across wires, relays, and ground connections. Your ditch lights or lightbar might be a good constant load to use so long as they’re acting up.

 

You have a loose connection somewhere. Check your accessory wiring at the battery positive and ground terminals since everything meets there. Check your main chassis grounds as well since you’re running the amp ground back to the body.

 

Gotcha, thanks for explaining through it all. I bought some wire cleaner and plan on cleaning up the harness and what's in there once it arrives. The new Cali Raised set arrives tomorrow and let's say once it's installed it works fine, what could maybe be the cause of the spliced fog lights? Maybe it's a coincidence that they randomly fell out? They're in line with the sidelights on the headlights and those are firing fine. That's what's confusing me there.

I had a Toyota employee mention that I could just buy the wiring harness that has the fog lights included, is that potentially an easy swap?

 

I've verified the connection and ground for the sub, grounded well. The lights are all grounded straight to the battery. Is there a diagram of stock ground points that I can use to go over them all?

 

So an interesting turn of events, the new set of fogs and wiring works... wonder if it was a loose wire under the dash, guess I'll see what it looks like. I've ordered a switch panel to clean up under the hood, get rid of relays etc so I'm waiting for that to get here before I install. Now I'm just lost on why the fogs stopped lol. I guess I'll see if they magically work again once the new ditch lights are in

 

Yeah, it’s unfortunate when a problem like that fixes itself. You’re probably right about it being a loose wire/bad connection; you’ll probably fix that by doing the rewiring. Let us know how it turns out!

 

Just curios, why was it totaled?

 

Original photos from the auction below! Won it for 3k back in early 2020. Had about 127k miles on it at the time, I think. Fixed photo is once it was picked up from a frame guy I know, $100 job. Crooked bed sat down and all.

 

Exactly why I hate electrical lol. Wiring that new switch box today hopefully, I'll see what the outcome is. Low hopes for the fog lights. I really want to replace all the battery cables with an upgraded kit but would rather someone else do it because I can't find a good guide lol. Thinking I will also add in the DRL relay and wiring and get a better set of headlights and I won't need to tap into wires for the headlights.

 

Very nice! I was wondering if flooding was involved. You could be chasing electrical gremlins for years. Best of Luck!

 

Thanks man! And no, not to my knowledge! There's a small water leak from the rear window but only when its heavy rain

 

Well, well, taking it all apart, installing a switch panel and cleaning up the previous owners fog light wiring fixed it all lol... lovely how that just works at times. Time to replace the relays inside and make it have some native DRLs