am2 fuse/Ignition Switch

Driving yesterday and truck dies. had it towed home looked over the fuses and seen the am2 30 amp fuse is blown.went to autozone got a new one truck started for about 5 min later it blew again. I looked at wires looking for a short but no luck. if been reading and a lot of people say it could be the Ignition Switch. has anyone had this happen? and will faulty ignition switch blow the fuse? thank you for any help.

 

I had the same issue 2 years ago, except when I replaced the fuse it never blew again. No one ever responded to my thread either:
https://www.tacomaworld.com/threads/am2-fuse-tripped.496735/

I shook every wire I could physically reach in the engine bay while the truck was running and I still couldn't get it to trip. The guys at the shop said it could have just been a fluke.
Still going strong 2 years later. I did stock up on a few of those fuses incase it happens again though.

 

Thank you for the info. after work im going to check once again for a short and then replace it again and hope for the best.

 

I had my truck just shut off and die at an intersection a few years back and had me tearing into every electrical component there was to check. Ended up being a small screw that holds the am fuse to the buss bar inside the fuse box... Yours could be making random contact causing it to short?


What led me to the missing screw was chasing voltages. I had a good 12.5 at the battery and the main connection to fuse box, but inside the cab (radio, dash, clock) I was only getting 3.5.

 

Might be good to know just what year engine trans etc

Getting any Codes ??

if this is a 3.4 check the igniter connection and coil packs connections

Ignition switch the fuse would open right away more then likely

 

it is a 2001 with the 3.4 / man trans. and thank you ill check both those connections

 

I looked at a few different year wiring diagrams and all of the 3.4's show that AM2 goes through the ignition switch then to the 3 coils and to the igniter, and that is it.
AKSavanaman is spot on checking voltages. If it takes 5 minutes to blow then there has to be some heat build up that you can trace. I am thinking take the covers off the column so that you can put your hand on the electrical portion of the ignition switch and feel it for heat. While you are doing this you can check for battery voltage at the wires at switch the White/red is the in +12v wire and black/red is the out wire, then to each of the coils then the igniter. If the voltages are at or near battery voltage you will need to preform a voltage drop test, not a resistance test, a voltage drop test. This test checks to see how good the wiring is at passing current/amperage. With the circuit loaded, meaning have the truck running, set the meter to DC 12v if a digital multimeter or 3v DC if an analog(swinging needle) meter. Place one lead on one side of the circuit to be tested and the other on the other end. If using an analog meter and the needle swings negative, reverse the leads. With the circuit loaded, anything greater than .3 volts is bad. If for example the meter shows 1v, start moving that probe closer to the first probe along the chain of devices, meaning start at the igniter, then move on to the coils then to the output side of the ignition switch then to the input side of the ignition switch. I hope that sometime in the trucks life someone hasnt put an aftermarket alarm in and just left the rats nest of wires and crappy scotch lock connectors.

 

A loose connection that gets hot will also cause the fuse to open if it arcs

Also check the ground getting loose with heat.(under the data link connector)

What about any codes to maybe point in a direction

Best guess a coil Pack starting to fail getting hot

 

I touched all connecters to make sure they was tight. got under the dash to check wires and I found a loose wire from the ign switch. got it fixed and went to put a new am2 fuse in and noticed that a piece from the old fuse was still in the socket. I removed it and out in a new fuse and the truck is running like a champ like a TACOMA SHOULD. thank everyone for your help saved me a lot of $$$$$ being able to find and fix it myself.

 

Awesome man, good to hear. Love a successful troubleshoot AND repair story

 

That's some awesome sleuthing man. Glad you shared that one, this could very easily be overlooked or possibly even never found lol

 

Sorry to fire up an old thread, but I am having this issue, and I've checked for any loose/burned wires. I haven't had any luck. As soon as I try to crank the truck, the am2 blows again. No other problems with the ignition as the motor is cranking, and all electrical works. Any ideas?