Why all of these issues suddenly? Bad relay?

Hey all:

I appreciate any guidance in resolving this issue.

my 2008 taco is a 6 cyl, and in general good mechanical condition.

I was traveling from Charleston SC to Colorado during Christmas week. For the first 12 hours it ran fine. As soon as I approached St. Louis, I heard a something odd. My speedometer died. My heat also died. There were a bunch of lights on the Christmas tree - abs, 4wd, check engine, and parking brake all illuminated.

I didn’t think anything of it. Truck was still running fine. About 20-30 minutes later, the truck started to stall and eventually died.

my initial thought was alternator (why would the battery die otherwise?), so I replaced that the next morning. I also replaced the battery.

This is where things get just plain odd.

the abs, check engine, 4wd, and parking lights are still illuminated. The speedometer still does not work. Neither does the heat. Nor do my power windows. I also hear this weird tapping noise from one of the pulleys (my initial thought is the AC)

The battery/alternator maintain constant volts around 11.90. I’ve seen that I should see around 13/14 volts while it’s running.

All of the relevant fuses look good.

I am stumped. Why all of these issues suddenly? Bad relay?

 

Have you checked the IG 1 and IG1 No2 fuses in the interior fuse box?

 

Did you check the fuses under the dash by your left knee?

 

I checked those with a meter. Maybe I should pull for visual inspection

 

If they appear to be good and you have a meter make sure they have battery voltage on both sides with the key on.

 

The strange thing I see here is, that the “Parking lights” are illuminated?
Is the headlight switch turned to off?

Can you tell us more?
Are the head lights off?
Are the outside parking lights actually on?
Or is it the indicator light on the dash that’s on?

 

Located the problem. It is the IGN1 fuse. It keeps blowing.
Ive changed it twice now.

 

Does it blow immediately when you turn the key on or when you perform a specific function?

 

Immediately

 

That fuse feeds alot of stuff but we can narrow it down some, unplug the IH1 connector behind the glovebox (you may set codes in the PCM doing this but they can be cleared) and see if the fuse still blows.

 

Also check the wires coming out of the ac clutch on the compressor.

I had the same symptoms you describe after some ac service at my local toyota dealership.

They had not fastened down the wired part of the clutch properly and the wires were shorting intermittently and blowing the IGN fuses and giving weird dash lights.

 

It is the time of year when rats like to nest in vehicles and chew up wiring... Look for freyed wiring or bad/coroded connection somewhere.

Sounds like you have a wire grounding where it shouldn't

 

Un

unplugged it and fuse still blew

 

Just to be clear this is the fuse that's blowing correct?

 

No, the one to the left of that IG1 no2

 

To clarify, the fuse blows the second I turn the key. Ac/heat is off. Lights are off.

 

Ok that fuse feeds even more stuff, the easiest thing to start with would be unplugging the alternator and if that's not it inspecting the wire to the alternator paying special attention to the light green wire.
I'm working on the list of stuff it feeds if that's not it.

 

Ok here's the list of what all it feeds:

Alternator (4.0L)
Clutch Start Cancel Switch (M/T 4wd)
STOP LP CONTROL Relay (W VSC)
Yaw Rate Sensor (W VSC)
VSC Warning Buzzer (W VSC)
Steering Angle Sensor (W VSC)
Differential Lock Switch (If Equipped)
Skid Control ECU (ABS Module)
Rheostat (Panel Dimmer Knob)
BATT CHG Relay (W Tow Package)
MG CLT Relay
HEATER Relay
Cruise Control Clutch Switch (M/T)
Power Inverter Switch (If Equipped)
AC SKT Relay (If Equipped)
Tire Pressure Warning ECU
Accessory Meter (If equipped)
Auto Dimming Rear View Mirror (If Equipped)
Body ECU

 

Thanks! What’s the best way to tackle this? Start unplugging things? Start unplugging other fuses/relays?

 

Like I said I'd start at the alternator and harness to the alternator looking for possible shorts to ground as that would be the most likely area for a short.

My method would be to have a test light in place of the fuse and watching it while unplugging stuff and wiggling wires until it flickers or goes out or dims.
I've attached all the diagrams that include the IG1 No2 fuse, if you need connector/Module locations I can get those too.

https://www.youtube.com/watch?v=oKCLzf4va7M