IG1 Fuse Keeps Blowing

2008 Tacoma TRD Sport V6. Factory tow package. I hitch up, plug in my 7way, check all my lights(all are good) and as soon as I take it out of park I blow IG1 fuse. I thought there might be a problem with the trailer wiring but I hook up to 2 other vehicles and all is well. Can someone help?? Thanks!

 

Does it blow with no trailer connected?
If it doesn't blow with the trailer disconnected the issue is more than likely in the trailer wiring or in the 7 way connector. NOTE: This connector is a common problem item due to the constant exposure to the elements.

 

Loads on the IG1 Fuse 10 Amp:

ABS (w/ VSC), TRAC, VSC, Auto LSD, Downhill Assist Control and
Hill–Start Assist Control
ABS (w/o VSC)
Accessory Meter
Air Conditioning
Back–Up Light
Charging
Combination Meter
Cruise Control (1GR–FE)
Cruise Control (2TR–FE)
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
Multi Mode 4WD and Rear Differential Lock
Power Outlet (115V
Rear Differential Lock (2WD)
Seat Belt Warning
Shift Lock
SRS
Tire Pressure Warning System
Trailer Towing
Turn Signal and Hazard Warning Light

 

Jimmy, No it does not.

 

Also, Jimmy, I hooked up to both of my other vehicles and pulled the trailer fine without issue(2019 Ram 3500 and 2020 4Runner TRD Pro).

 

Something isn't wired correctly either on the truck or on the trailer or you have a short on the trailer.

If you have the factory 7 way the only thing the IG1 fuse feeds on the trailer plug is the reverse lights (which most trailers don't even have).


This is how a standard 7 way plug should be wired (note colors may vary but pin designations are always the same).

 

Dm93, what still doesn’t make sense is that it’s only blowing the fuse on my Tacoma. I pulled out both tail light assemblies looked for shorts and tested all circuits that I know to check.

 

Inspect the trailer plug and wiring on the Truck. It may have an issue that only shorts out when the trailer is plugged in.

 

Take the plug apart on your trailer and see if anything is hooked up/touching the center pin, if it is then you need to trace that wire on your trailer and see where it goes.

 

Thanks guys…I’ll do that now.

 

I didn’t find anything out of sorts.

More context: Trailer is 8.5x17 wired for 30amp with a batter and charge controller. Any chance this could just be more of a power draw on the Taco??

 

The 10 Amp IG1 fuse powers the backup lights via the Reverse Switch on a Manual Transmission and through the Park Neutral Switch Reverse contacts on an Automatic Transmission.

If IG1 is blowing with the trailer connected and NOT when it is disconnected the issue is more likely an issue with the trailer. Are you using the same 7 wire connector on the trailer for the other vehicles that don't blow a fuse? Have you towed this trailer with the Tacoma before?

 

Jimmyh, yes, it’s the same connector for all three vehicles and this is the first time to hook up to this trailer with this Tacoma.

 

Did you take a peek inside the housing at the actual spade connections? If it's green in there, you've probably found your problem. Same goes for the junction connector further back in the wiring harness.

 

Too Stroked, that was one of the first things I checked. I didn’t see anything bad but went ahead and cleaned all the connections on the truck and trailer. And yes, it is the factory tow package with factory wiring.

 

That's good. You've eliminated one of the major causes of trailer wiring headaches. You wouldn't believe some of the "green gardens" I've seen in rarely used trailer connections.

 

I have to be missing something…I can hook up, run through all the lights and as soon as I take it out of park THATS when the fuse blows. I’ve been through about 7 fuses now…chasing leads and retrying. I’m lost.

 

Has the wiring on the truck plug ever been messed with or the plug replaced?
Would be the only explanation aside from the fault being on the trailer.

 

Try this as the power passes through the Park Neutral Switch reverse contact.

Replace the fuse.
Place the transmission in Neutral.
Plug in the trailer harness 7 way connector.
Then check the lights (without putting it in reverse) to see if the fuse blows.

Possibly an issue with the Park Neutral Switch.

 

I might have missed it, but did you check the truck side? The 7-pin socket, or T12 as Toyota calls it on that pdf