IG1 No. 1 Relay location?

Hello! I am trying to find an "IG1 No. 1 Relay" in my Tundra but cannot find any mention of its location in service manuals or wiring diagrams. Does anyone know where it is? Thank you!

 

It will be in your fuse box under the hood. The bottom of the lid will have a diagram.

 

I believe it is "integrated" into the fuse box. I know I have looked through mine a few times and some of the relays are not visible/easily removable.

I have to ask out of curiosity why you are needing to remove it?

 

I have probably stared into that box for a half an our, it is not there physically nor on a lid diagram. It is not even listed in the official Toyota repair manual among other relays. I can only find it in the wiring diagram.

 

I had electrical gremlins, sporadically, half of the systems would just not initialize on the startup.

Symptoms:

All happens at the same time upon an ignition sequence, never happened while driving.

- ABS light is steady on
- Column shifter locks out (have to physically unlock it by pressing an unlock button)
- No blinkers
- No power windows
- No A/C, blowers, no nothing
- No radio
- No central locks
- No ABS or traction
- Some of the gauges on the dash work, speedo and tacho (?) don't work
- Headlights also work normally
- there might be something else that doesn't work, I forget

Engine works fine and the car drives normally. When trying to scan with the Techstream while the malfunction is present, it does not see the following computers:
- ABS/VSC/TRAC computer
- Tire Pressure Monitor
- Air Conditioner
- Accessory Gateway

The problem comes and goes sporadically without leaving any meaningful error codes. (attached a pic for reference)



I tracked the issue down to this relay, all of the mentioned systems get signal/power from it.

Now I am hopeful that someone knows where to find it.

 

@RainMan_PNW

 

Small update.
It seems that I was able to trace the wires to Main Body ECU that is under the dash on the driver's side. "IG1 No. 1 Relay" seems to be integrated inside that module. I will wait for a response from more knowledgeable members of the forum. I tis a big ticket item to replace, ~1200 Canadian dollars (Toyota P/N 82730A). I hope that the relay is serviceable. Wiring seems to be intact in that area but can't be too sure. Will be looking for a potential water damage.

 

Yes it is integrated into the main body ECU you have circled. I doubt these internal relays can even be removed or replace.

This entire circuit is the Driver Side Junction Box. All of the wires go to connector DD which is one of the bigger plugs on the main body ecu.

 

Could your ignition switch be going out and not the actual relay that failed?. As you see below the ignition switch IG1, is the trigger to close IG No1. Relay, IG No2. Relay, IG No3. Relay.

Having all 3 of these relays open will not send power to any of the fuses on the other side of them. I think you have enough systems failing that more than one fuse is not getting power.

When it happens again, you could bypass the ignition switch by sending 12V+ into the Light Green wire on Connector DD Pin #43. Engergizing this wire should make all the relays close and all your systems come back online hopefully.

 

I have thought about that, now I need to wait until it fails again to see if the wipers and backup lights work. My memory is fuzzy, but I think that they worked last time it failed. If they work, it would mean that the IG1 No.3 Relay still gets the signal from the ignition switch and the Main Body ECU is busted. If they won't work, then I'll dig into an ignition switch.

I'll go get myself busy trying to replicate the problem.
Thank you Jeff!

 

Yes if you have proof one of the three relays is closing and operating properly you have have an internal problem in the body control module.

Might just permanently set the voltmeter up on the green trigger wire and drive/wait. Under normal operation the wire should have 12V, if voltage drops to 0V when your systems don't come online you would have your answer.

 

Once again Jeff genius of the Tundra wire diagram comes through!

 

I just hope it helps him figure out what the real problem is. If the relay has actually failed I’m not sure the best way to replace it.

 

Late to the party here (I've been swamped lately), but Jeff's conclusion is exactly what I'm thinking. That DA connector is your main power feed from the engine bay into the internal ECU and all of the associated switches and fuses. Your ignition switch triggers the coils in those three relays, and then those relays send power to the individual fuses downstream that then power all of the circuits they feed. If you haven't already, work backwards from each individual system that is failing to see 1. what fuse serves it, and confirm the fuse is good, then 2. what relay feeds that fuse, and then look to see if ALL of the affected systems are on ONE relay, or if they are scattered across the three Ignition relays and if there are any systems on those relays that are still working (if one system powered by the relay is good, then the issue may still be internal to the ECU, just not in the relay itself).

Finally - if you do have to replace the ECU, I would recommend looking at wrecking yards or ebay for used units - you should be able to save a fair amount that way.

 

I have a good update.

The glitch have finally showed itself again today and I was able to track it down with the multimeter.
When the problem appeared, white cable that goes to the ignition switch had 0 volts on it. I have looked further into diagram and found that there is a fuse AM1 that sits on that line. I have opened the fuse box that is under the steering wheel and started pulling out the fuse, the key was in the ignition and ignition was on, all the problematic systems came alive.

So it is either a loose fuse or a loose contact in the fuse box, everything seems to work alright after I wiggled the fuse. Might take apart the fuse box later to see if there is anything wrong with contacts, it works great for now, as is.

The mystery has been solved!
Thank you everyone for helping me!

 

Replace the fuse first. Look up in there to see if the contacts look dirty. I remember a year or so ago when I realized that one fuse could kill half the truck and thought wow this could be a real problem one day.

Interesting design by Toyota. I am sure the need for the fuse exist but when you start having problems here it can be confusing.

 

Awesome to hear you’ve at least got it isolated now!

 

I figured it’s a pretty normal “double protection” setup. Kind of like your house panel having a main breaker and then individual breakers for each circuit. It ensures you don’t overload a single circuit OR the full capacity of the system (or sub-system in this case).

 

Just wanted to thank Tundravod for posting the solution to the problem and also thank Jeff_5_7 for his many posts discussing wiring schematics. I recently helped a neighbor whose Tundra was not charging after replacing the generator/alternator (and accidentally breaking the plug connector and using an aftermarket one with pigtails, which may not have been connected correctly), battery, ignition switch (because the key broke) and not having the windows, neutral safety switch, wipers, etc. work. Unfortunately, the owner could not remember the order of the sequence of events. I verified the alternator was not putting out voltage and the IG wire was not getting any voltage. After reviewing the schematics, I went about searching for and inspecting the various fuses and came to a dead end trying to find the IG No. 1 relay after discovering the LH IG fuse had no power. Replacing the AM1 fuse ended up being the immediate solution. Why the fuse blew is unknown, but I surmise it was related to the attempts to extract the broken key and subsequent ignition switch repair.