hdrox88

Hello all, I just registered here on YotaTech as I need some help. I have searched on here before and this forum has helped me out in the past, but I am out of ideas now with my current dilemma.

I have a 2002 Tacoma with the 3.4L 5VZ-FE and an auto trans. 2WD as well. The truck has what I would consider to be an extensive amount of modifications so that may play a part in what is going on here. It is not your average "PreRunner" tacoma. It is fully caged, long travel with 4-link and all the other fun stuff.

Now on to the issue. I am popping the 10A gauge fuse immediately when the ignition is turned to the ON position. I got the truck a few months ago and drove about 100 miles or so with no issues. Then while driving, my speedo, tach, temp, and odo went dead. Fuel stayed where it was at. I checked fuses and the mentioned 10A fuse was blown. I replaced it and all was well. After about 50 miles, it happened again. Then again after about 20 miles. And then again after <5 miles. Well that last time it popped I was on a 60 miles round trip and I just kept going cause it didn't seem to affect the trucks performance. On my way back home from my destination I made a pit stop. Went to leave for home and it wouldn't start. Got it jump started and was on my way. After about 10 miles, I noticed a severe performance loss, it had almost no power so I pulled off the road to see what was up. I noticed that my aftermarket e-fan was running VERY slow so I shut it down. Tried to restart and nothing. Dead again. Got it towed home(sad day in the world of Toyota). Tired and frustrated, I left it for the next morning.

Voltage was resting around 10 volts. I jumped it and with the second vehicle still attached with both engines running voltage was around 12.5volts. I disconnected the vehicles and voltage dropped to around 9 volts and I watched it drop to 8.5 volts before I shut it down. I start thinking bad alternator, but I ended up having both the battery and the alternator tested and they were good. Upon reinstalling the alternator I noticed a vacuum line had come loose from the K&N intake tube. I am assuming that is part of what caused the loss in performance so I fixed that. I decided to trace the wires from the trans connectors and that is when I found that the harness that connects to the trans had melted on the exhaust(the manifold that crosses over from the driver side between the engine and firewall). I pulled back the wire loom and the damage was not as bad as I was expecting. There was a shielded set of wires. There was a sleeve that looked like the size of about 10GA wire but it had three wires inside of it. The sleeve was black with a pink stripe. Inside the sleeve was a purple wire, orange wire, and a bare wire. The purple wire was the only one damaged and it was touching that bare wire. I tested that bare wire and it has continuity to ground(not sure if it is supposed to be grounded or not). I cut out the damage portion of the wire and soldered in a new piece of wire. I wrapped everything up and reconnected everything thinking I had fixed it but upon turning the key the fuse popped as soon as I hit the ON position. I disconnected all the connectors in that harness and tried another fuse to see if one of the sensors was shorted out internally but again, I popped the fuse. I tested all the pins on the connectors for continuity to ground and some had none while a couple connectors has two pins that went to ground somehow. I am not sure if they are supposed to or not. The wire colors on those pins were red w/black, black w/red, pink and blue. One connector was large and had like 10 pins on it and the other had only 3 pins and was connected to the very tail end of the trans.

This is where I left off last night after several hours of attempting to find the problem. I am sorry for the long winded story but I figured that the more info I give, the better the help I may receive. If anyone can point me in the right direction it is much appreciated.

Thanks in advance, Adam

hdrox88

I did some more trouble shooting and more web surfing and finally got it straightened out.

This site here is great:
http://www.ncttora.com/fsm/

I ended up tracing a black w/red wire up under the dash and knowing that the cage work was behind the dash I started pulling the dash. I ended up finding that one of the screws on the back of the gauge cluster was touching the cage and shorting out the whole thing. I put some insulation in the trouble spot and presto, what a relief.

swampfox

It is a good feeling when you are able to solve a problem your self. Glad you got it fixed.

Ron Helmuth

dang good of you to solve the issue yourself and then let people know what it was. Previous owner electrical issues can be pretty annoying-this is a good way to let others learn by what happened to you.

TheDurk

Gee, and I was just about to suggest it was one of the screws hitting the cage....

Seriously, congratulations and thanks for posting. This is one where a forum can't help much other than point you to the wiring manual (that you found yourself) and encourage persistence, which you obviously have.