Strange Problem with IG1 No.2 Fuse

I have a very weird issue in my 2014 DCSB 6-speed Manual Tacoma that I am wondering if anyone has ever had before. Been looking through the Google and TW, but can't find anything that quite describes my issue:

The issue is with my IG1 No.2 fuse. It's a 10A fuse that controls (at least partially): anti-lock brake system, stability control, stop lights, charging system, fuel injection system, air conditions, instrument panel light dinner, clutch start cancel switch, rear diff lock, power outlets, and tire pressure warning system. I used to have a tap-a-circuit installed on this fuse and noticed that after I was in the truck for a while, like 2+ hours, with the heater on (during winter), all of the affected systems warning indicators would illuminate, and my air blower would stop working, and the windows would stop working. Most of the time the issue would fix itself after I turned the truck off and restarted it.

So then I took the tap-a-circuit off of that fuse, thinking I was somehow pulling too many amps and overloading it; The problem stopped for a while....until this week. Now that it's getting balls hot every day, the problem has started again. Everything works fine in the mornings, but when I head home from work and the inside of my truck gets super hot; all of the warning indicators illuminate, air blower and windows stop working. I did a little diagnostic work and put in a 15A fuse yesterday just to check and it started working fine. I removed that a put in a different 10A fuse, but that didn't fix it either.

My last diagnostic was to clean out my air blower and check the resistor on the AC system to make sure there wasn't a short in a wire or any junk in there that might cause it to pull more amps than it should, but that didn't solve anything either. I also unplugged the AC blower just to remove that from the equation altogether and hopefully rule it out, and the problem persisted.

This is super odd and frustrating since I'd love to be able to either roll my windows down or run my AC when it gets hot! If anyone has experienced this or something similar, please help! My other option would just be to slowly go through each system and check for shorts, but as you can see above, that list is long.

 

Fuses don't self heal like a skinned knee. You need to look elsewhere. Possibly ignition switch?

 

Yes that is some list you have to go through. If I understand it doesn't blow the fuse? And it can be reset by cycling power via the ignition switch?

Yoiu could try isolating each of those circuits one at a time until you find the problem circuit. It will take some time...

IG1 No.2 supplies the following circuits:

ABS (w/ VSC), TRAC, VSC, Auto LSD, Downhill Assist Control and
Hill–Start Assist Control
ABS (w/o VSC)
Accessory Meter
Air Conditioning
Automatic Glare–Resistant EC Mirror
Charging
Cruise Control (1GR–FE)
Cruise Control (2TR–FE)
Door Lock Control
Electronically Controlled Transmission and A/T Indicator (1GR–FE)
Electronically Controlled Transmission and A/T Indicator (2TR–FE)
Engine Control (1GR–FE)
Engine Control (2TR–FE)
Headlight
Illumination
Interior Light
Light Auto Turn Off System
Multi Mode 4WD and Rear Differential Lock
Power Outlet (115V)
Power Window
Rear Differential Lock (2WD)
Shift Lock
Starting
Stop Light
Tire Pressure Warning System
Trailer Towing
Wireless Door Lock Control

 

OK - I'll add my 2 cents .....

Lots of failure points to consider - I doubt the fuse is the issue if it's making good contact. When I look at "My" 2006 schematics (i know not the the right one but pretty similar) I tried to find something common. It's probably only one problem (hopefully) so I started with just one of the items you mentioned and traced the schematics. I started with power windows .... Yes, this fuse is in the circuit - but NOT the power to the Windows - just power to the relay. This Relay gets power from IG1 No.2. Via the Body CU unit. I'd test the 12v power from the fuse to the BCU, The Ground from the BCU to the Bat NEg. and then the Power out from the BCU to the Pwr window relay coil AND the Relay coil to ground. I'm thinking that this is so widespread that a ground point that ties to multiple control modules is frayed/bad and heats up do the high resistance and drop the 12 v to much lower. ???

Make any sense??

 

Also, I see other connections to the electrical modules from other battery source/connections. Check / Clean battery connections (pos + neg) and bat to ground at gnd point etc. Check that your charging circuit is working as well. If the battery is dying after long time running the voltage drops and causes all sorts of weird issues.

 

Have you resolved this issue yet?
I ask because I am having the exact same issue!
But to be clear, My IG1 no.2 fuse blows as soon as I turn the ac blower on.
When it blows, I experience the same symptoms, lots of warning lights, blower stops, speedo quits working, windows won’t roll down.
I have a 2006 Tacoma double cab. I live in AZ and my ac runs constantly!
I have probably replaced the blower motor at least 5 times and blower motor resistor more than once. It seems that the connectors/ wires are not sized correctly for the motor amperage draw. The wires are constantly burning up at the connector which leads to weak connection. I have replaced the resistor connector several times but now have finally had to replace the blower connector because the wires have become too brittle and thin at the blower connector plug. Will need to replace approximately 2” of wire with the plug and will order it from the dealer.

I assumed that the wires were shorting together at the burnt ends of the wire so decided to isolate them and unplug them from the motor. Turned blower on and immediately blew the fuse each time. I am able to keep the fuse from blowing as long as I don’t turn the blower on.
Any Idea what may be blowing the fuse?
I am going to try unplugging the resistor in a bit to see if that might be the issue but saw this post and thought you might be able to prevent an unnecessary headache!

 

I had this problem - turned out to be my AC compressor was fubar.

 

Unplug the mg/clt relay in the under hood fuse box and I bet your fuse won't blow.

The only part of the blower motor circuit that the ig1no2 feeds is the relay coil. Not really possible for that to blow the fuse.

The ig1no2 fuse also feeds the mg/clt relay contact and coil. When the contacts close, power is sent to the compressor clutch. More than likely, your compressor clutch is cooked and shorted.

 

Hello,
I'm having the same problem on my 2013. I've replaced the alternator, blower motor, reostat, cleaned the battery terminals. After replacing the blower it lasted a couple hours, I turned the heat to high on the blower and popped that dam fuse again.

 

My issue ended up being quite unique and doesn't sound like it will apply to yours. But for anyone that stumbles on this thread in the future, it was the contacts within the fuse block that weren't making good contact with the blades on the fuse. I had a suspicion it was related to something expanding since the problem would only surface during the hottest days/weeks of the year (which was super unfortunate since the IG1 No.2 fuse controls the A/C and the windows, rending my truck a rolling hot box). The contacts within the fuse box has widened just enough so that when it was super hot and there was some sorta expansion, they didn't make good contact anymore. This was likely caused by the tap-a-circuit, which has thicker blades than the fuses that are used.

After adjusting the width of the fuse block contacts, the fuse fit in nice and snug. I haven't had any issue since.

 

Not sure if this is any help but '09-'14 Ford F150 had a problem because they used too small of a fuse holder and mini fuse for a high amp load control to the fuel pump and others. The fuse holder could not handle the heat and melted the copper wires away from the connectors inside the fuse box where it was hidden causing arcing, and disconnecting the circuit, resulting in a mystery no start condition.
Sometimes it would blow the fuse and most times not, sometimes it would cool off and reconnect power somehow. Which just prolonged the agony of being stranded at random by a mysterious problem.
Finally after years of the mystery NO START condition the issue finally got solved and ford issued a tech bulleting and fix by tapping in before the fuse box and adding a larger fuse and fuse holder

 

Some Hondas used to have the same problem with the starter relays - connections breaking in hot/cold cycling and when too hot, the parts would expand and break contacts in the relay unit. Mystery problem that would go away sometimes once you opened the car up and got into the glovebox and dash to look at fuses for troubleshooting, which would of course equalize the temp inside the dash where the relay sat. Madenning.