Multiple Electrical Failures on 2005 Tacoma

Hey-
I just posted this on new members board. I don't want to be redundant.. That is to be repetitive or say the same thing over and over again or repeat things... BUT... I've got a 2005 TRD 4WD V6 with about 190K+ miles. The electrical system has freaked out!! I have an aftermarket stereo that worked fine for a couple years. Now... Airbag warnings go off and on intermittently... Stereo blinkned on and off, AC fan is fine. Cold air comes and goes.. Clocks off or dims.. Interior lights work sometimes.... not others. I think the truck is pissed off. My local mechanics cant find anything. Ideas?

Don't know too many folks with this many miles... So could be they just melt down after 190K.... Scary!! Or, could be pissed that my wife and I broke up and we used to have great trips together. One never knows, but I hope for a scientific explanation from this forum. the Truth is out there!!

 

is this all true under battery power or only when the truck is running? PS. you have a 2nd gen

 

DOH... Yup. 2nd Gen for sure.
Problem occurs when truck is running.

 

I've got a 2005 TRD 4WD V6 with about 190K+ miles. The electrical system has freaked out!! I have an aftermarket stereo that worked fine for a couple years. Now... Airbag warning lights turn on.. then go off. Stereo works for awhile, then stops. AC fan is fine, but air is cold/then stops blowing cold air (fan motor was replaced).. Clock goes off or is on and very dim. Interior lights work sometimes.... not others. I think the truck is pissed off. My local mechanics cant find anything yet. Ideas?

 

id start by checking all the grounds

 

Dang 190K on an 05 is impressive, over double my 05 mileage. Maybe time to start looking into a 12' or 13'
Just wishful thinking... but I've never heard of anything like that. I guess check all fuses, ^ grounds, and maybe other big electronic components like the battery and alternator.

 

I agree with fixer, check the grounds. There's a ground just below the cigarette lighter on the passenger side. I'm not sure if that grounds any of the stereo stuff or any of the lights but it's in the general vicinity and could be your culprit. Otherwise, check the grounds under the hood for starters.

 

The tough thing about electrical is that often if you take it to a mechanic they don't have and don't want to put in the time needed to actually trace down a problem.

Really sounds like you need to methodically go through the main systems. Many people and shops are quick to pick on aftermarket additions like the stereo (assuming amps etc.) as the problem. Often they can be an issue, but then not always. When I worked dealerships I often found screws run through wiring harnesses, seats mounted on top of wiring harnesses and smashing them etc. etc. right from the factory. I even found a Thunderbird once (yes, Ford and yes it has been a long while ago) that had the totally wrong harness in it from the factory.

So, to get to your issue with some thoughts. When these weird electrical things are happening, does the engine cut out or stumble? Does it seem like the electrical system shuts off and then blinks back on again?

How extensive are any add on items like the audio system? If full on amps etc. have you tried disconnecting them and seeing if that makes a difference?

Have you disconnected, cleaned and tightened all the battery ground connections?

Have you experienced an issue with slow sluggish starting or a dead battery after the vehicle sits a while?

Have you had the battery properly tested?

Do you ever smell any burnt wiring type acidic smell?

Brain floating really random here, but I remember once someone having an issue with weird electrical issues and it ended up being their ignition switch being faulty. In their instance the key would not return fully from the start position and would bounce as it were right on the edge between start and run. In run you have power to everything, in start it would cut the power. Probably way off base and have to say this was not on a Tacoma, but as I said, random thoughts.

How corroded are the battery, fuse box and alternator connections? Clean and tight?

Have you had the alternator tested?

You could aways look for a draw on the system indicating a short. With everything off, disconnect the negative cable and connect a test light in line with it. By that I mean, have the negative cable not touching the battery post, connect the clip end of the test light to the cable end and then touch the pointed probe end of the test light to the negative post. You are looking for the test light to light up. If it does then you have a current draw with the system off that could indicate a short somewhere.

Oh, when you are doing this test, have the doors all shut as if they are open then the dome circuit is going to show a draw (ie light the test light up). Anyway, if the test light lights up then what you can do is pull and replace one fuse at a time to see if you can get it to go turn off. Whichever fuse you pull that turns the light off is the circuit that the draw is on. For example, you pull the power outlet fuse and the lamp goes off. That would mean that there is an issue with the power outlet system somewhere from the fuse to the outlets.

I'd also go thorugh all the harnesses, check that all the plugs are clean and tightly connected, make sure any little ground loops are clean and tight, look for any areas where the harness might be rubbing on something sharp, pinched flat/crushed (often you'll find wires shorted together in the flattened area) or if there is a screw run through it somewhere.

All your relay and fuse connections clean?

Well, I'll stop there for now. As I said, some very random thoughts and questions. Might be totally off base. Electrical can be frustrating, but if you are systematic you can often find the issue just might take a bit of work. Then again, might be something really simple.

 

check, double check, and triple check what you look at. I popped a fuse that killed my windows, ac/fan, interior lights, radio.. while I was off-roading.. I had to run with the doors open until I found it...

 

I believe it's the tail light fuse that will kill the interior lights. I had that happen when I hooked up to a trailer with corroded wires. Lost my tail lights and all the interior lights. I didn't check the stereo, A/C fan or windows at the time though.

 

Here, probably better than my rambling post. If you end up having to get into the wiring extesively to find an issue this is a link to the electrical manual for your year.

 

Negative this case was Ign 1 No.2 fuse

 

The only time I have seen this type of issue is when the Slip Rings in the Alternator get worn out to where they are shorting the electrical system. It did still charge the battery.

I spent 3 weeks tracing wires before finding this out. It sounds exactly like what you have. Replaced the alternator with a rebuild and ran it for another 10 years.

My vote goes for the Alternator itself.

Let us know when you find it.

 

Martie got it! There was a shunt under the fuse box that connected 3 different circuits. One of the legs was partially fried. 2nd mechanic I took it to figured it out. Thanks everyone for your help.

 

Correction- That was Ben the moderator that nailed this!
Thanks again!!

JT

 

do you happen to have a new link for this?

 

The short pin is only a jumper connector and not an actual fuse. Its the white fuse like connector seen on the left side of the engine fuse block with red "ST" stamped on it.