2008 Tacoma suddenly won't turn over, won't start

I drove >4 hrs yesterday, then stopped for ~1 hr and tried to start my 2008 Tacoma (automatic). Wouldn't start. Tried jumping it, nothing. All systems power up, lights & radio all work, but won't even turn over; no clicking, nothing. Battery shows almost 12.4V, even after multiple attempts at starting through all this diagnosis. Battery terminals are all clean and tight.

I checked all fuses that I could remotely think might be related, under dash and next to battery, and swapped out starter relay, all are fine. I put in a new ignition switch, no change. I pulled the starter and had it bench tested (2 places), both tests showed it's working fine. I tried starting in both P and N. No difference

I tried a voltage test on the signal to the starter (with starter pulled out, put positive probe of multimeter into connector [from battery] and negative probe on truck frame) and got 0 volts when someone else tried to "start" it. Shouldn't that have been >12V? Not 100% positive I was getting a good connection with probe, but don't know how it could have been any different. Tried this for both the old ignition switch and new one. No change. If that starter connector is not getting juice from the battery, that's obviously why it won't start but what would have changed to cause that? All wires looked to be solidly connected and in good shape.

Any other suggestions??

I've had this truck for ~18 months and had no other issues with it. It had ~108k miles on it when I bought it; now it's got ~127k. There was 1x a few months ago when it took me 2 tries to start it, but the weather was cold and it was early in the morning. I figured I let go of the key too soon. Then last week the left front turn light went out. I replaced it; it worked fine for ~3 or 4 uses and then it went out again. No idea if that's related, except it's another electrical abnormality in a short time.

 

Yes, you should have 12v at the small wire when cranking, and 12v at the large wire always.
Attach a jumper wire to the small terminal on the starter and tap it on the main positive post (in park, lol), of the starter, or go to the top and use the battery post if you prefer, if it starts then you’re not getting a trigger signal to the starter and need to do some digging, could be as simple as a park/neutral switch, or brake light switch.

 

TRCKTRK, thanks for the quick reply. I'm a little nervous about using jumper wires, especially if I'm underneath by the starter (even if it is in park)! Are you saying I need to connect the jumper wire from the small terminal connector on the starter (with the wire from the battery removed) and the positive post on the battery? That's a long jumper wire.

 

Yup, if it makes you feel any better I’ve done it probably a hundred times, and no issues, lol. If someone is there with you have them sit inside and hold the brake if you’re worried, but as long as it’s in park you should be fine.
The big wire on the starter goes right to the battery, but the small one is the trigger from the truck to start, so if you have a jumper wire with a small alligator clip, clip it to the trigger on the starter, yes, with the truck wire disconnected, and touch the other end to the battery or big cable, you will see a spark (wear glasses if you have them, but I don’t) and the truck may begin cranking over

 

It's worth a try. At the bare minimum it will save me the $80 tow charge to move it from the parking lot where it's stranded!

 

He said it was bench tested at two shops.

 

Eyes are foggy. Ok. Deleting haha.

I would be using voltage drop as the OP is suggesting.

One thing I've seen with Tacomas is the main junction relay can loosen off, so I usually tear down into the fuse panel and visibly inspect it, they can cause all sorts of haywire. You can also see if there's burn marks to relays etc.

 

It was a long post!

 

I’d head to the STA Relay and go from there.

See if this helps.
I don’t want to have to write it all again.
It’s easier to just link to it.
https://www.tacomaworld.com/threads/09-tacoma-no-power-to-starter-relay.695105/#post-24582925

 

Yeah, sorry for the long OG post; I was trying to prevent a lot of suggestions of things I'd already tried. I only tested the starter relay (and horn relay; swapped them out to see if they each worked in either slot). I did not check the main relay (EFI). I'll check that out when I try to jumper it tomorrow.

 

You need to see if you have power and control to the relay.
It’s a lot easier to get to, and can point you in the right direction.
That way you don’t have to test each component individually.

The relay will cut diag time in half.

 

Wiring diagram and relay terminal layout if that helps you.

 

Thanks man

I see you over in the other link. I was hoping you’d pop in.​

 

Yea I saw this earlier, I just now had time to post it.
By the way OP you said your left front turn signal quit, the starter relay gets it's ground from the same ground point (EB) on the left fender you may want to check those grounds there before proceeding.

 

I missed the part about the turn signal.

 

Thanks, TnShooter. Sorry to ask for the "Dummies" version, but let me see if I've got this.
You posted in that other chat that Pins #5 & #1 on the STA relay should have power when cranking. So do I connect my multimeter to pin #5 (and ground?) to test that? Just looking for continuity (when cranking the key) or a specific voltage or what? Then do same thing between pin #1 and ground? And where is the safety switch?

 

Thanks DM93! I'll check that EB ground first thing!

 

You are looking for battery voltage on those pins when cranking. 12v
Yes Red prob on the meter to relay pins. Black probe ideally to battery ground because you KNOW the battery ground is a good ground.

You are looking for continuity between pin 2 and battery ground/ body ground. Which is what Dm93 is saying to check.

 

Also, don’t jam the meter leads down in the relay socket. You don’t want to damaged the sockets and make them open up and fit poorly later. Just touching metal is fine. Don’t force them in.

 

Perfect. Thanks!