Why can’t I get my 2015 to start

Hey yall,
So my 2015 TRD won’t start. 4 days ago I noticed the feel and sound of The engine turning over was a little strained, so I popped the hood looked at the battery, noticed that the terminals were quite corroded and it looked like corrosion on the wire so I put new terminals on it thinking that would solve the problem cause now it’s not even turning over it’s not clicking. It’s doing nothing yet,There seems to be plenty of juice for the radio,headlights, etc.. I towed it to the dealership because I have an extended warranty and they work with this particular company. I thought that they would solve the problem lickety-split and then I’d be on my way. Nope! I got a call this morning and they said they refused to work on it because someone had changed the terminals on the battery cables and in order for them to work on it, They were going to have to get all new harnesses so they weren’t liable for some stupid thing that I don’t even remember, but it would’ve cost me thousands and thousands of dollars to do this! Seriously???All because I tried to save serious money,do it myself and Take care of an obvious problem the terminals had!!now they seem to suspect that it was the ECU unit does it seem like that is the answer because I don’t think it’s the starter because there’s no clicking no nothing Sound like it would be the ECU Please help me I’m desperate I can’t afford to do it with the dealership!

 

If you didn't replace the battery, get it load tested. Lights, radio and 12 volts doesn't mean anything if it won't pass a load test.

 

If battery proves good, check for loose connections at starter. Also check ground from chassis to engine.

 

Thank you Gents for the advice. I would do both of those things and get back to you if that’s not the problem. This is baffling me because it sounds like there is no connection to the battery whatsoever. There’s no clicking there’s no turning over the engine whatsoever, it is just nothing

 

There's no mention of the age of the battery. How old is the battery?

 

Check:
Battery
Your new terminal connections
The actual cables themselves (could be corroded)
I highly doubt this is ECU
A starter problem is possible, the UR series motors are subject to starter failures more so than the old UZs.

 

Is it in park?

 

The truck is in park A year old And there was corrosion on the cables and that’s why I put new terminals on the cables to work on the vehicle without putting all new harnesses on which would’ve been thousands of dollars and I just can’t afford that. Thank you so much for replying to me. I appreciate it

 

Can you take some pictures of the top of the battery installed on the truck, and the engine bay in general? There are some pretty good eagle eyed mechanics in here. Good luck!

 

Any follow-ups here? I've had a recent intermittent starting issue and need to start digging into it before my lease on my daily driver is up in January.

Notes:

Battery - newer, tests fine (I've been through 2 brand new batteries as well, so unlikely it's the issue; I have a tester that does load and last time it was 100% battery health)
Running - voltage has been lower than normal lately. Typically runs 13.9-14.1, but it's been ~13.2-13.4 more recently

I've checked while it's sitting there and it doesn't appear that there's a draw when it's off, or at least not when I checked.

Currently battery shows 12.1v, but it just clicks, no turning over. I'm suspecting the starter or alternator, but it could also be the wiring, or something else I suppose. The battery terminals are newer, but testing the voltage at the actual battery terminals shows 12.1, moving around to different areas on the wiring near the battery I get reading anywhere from 3/4v to 12+, so maybe I need to replace or clean up the wiring?

 

If you are reading 12.1 VDC on a battery with no load you have a problem. 12.6 is normal. Try checking voltage while trying to start the engine.

 

Been hot in much of the country lately, heat kills car batteries.

 

Possible, but I'm going to say unlikely. I drove it Friday and it's mid-60s right now. I think it's a bigger issue than just a worn battery, unfortunately...

 

Here is the update. It was towed to a different mechanic. They changed out the starter relay switch and that SHOULD have been the end of this chapter but NOPE!
Now,the truck is struggling to atart like before but now,add not getting fuel properly wher starting it. It struggles with power and fuel it seems. HELP?

 

I've got it on the charger now, I'll see how it goes in the morning. I'm suspecting I may need to clean or replace some wires, as I'm getting pretty inconsistent readings at different locations all near the battery. 2011 with 150k on it, so it could simply be corroded wires. I'll run through some of the other diagnoses this week as I have time.

 

Morning update on my truck - battery showed full and 13.6v after charging. Still the same result: click, no turnover, no start. This isn't the first time it's done this...in the past I've gone back a while later and it has started.

Any suggestions on the process for troubleshooting? Here's what I'm thinking/have done:

1. Re-test the battery with my tester and a load (see what it says)
2. Pull/test the starter relay - I tested the contacts and the one that should have power (when off) does, nothing at the other three; also tested resistance on the relay @ 118 ohms (seems fine in that regard)
3. Pulled the AM1 fuse - looks fine
4. Re-checked battery voltage, holding at ~12.57

 

Pulled all the fuses that I found in videos to check and they all look fine. Tapped the relay and no change at all. Did a visual inspection of all the wires/cables I can see and nothing obvious stands out to me as having been chewed or any disconnects anywhere. I do need to get under there and/or pull the wheel well flap to see if I can see if there's anything disconnected. Next step I think is going to be to jump the relay just to verify that it's not the issue...

 

Just went out and jumped the relay - same situation, clicks but doesn't even try to turn over. Ugh...starter? When I try to remote-start it, it clunks and there's a whirring noise, not sure if that's the starter but it sounds like it's coming from the same general area.

How would I go about whacking the starter? It's pretty hidden in there!