07 4Runner won’t start. Help

So. The other day the charging light came on. And it would start and shut off. Till the battery went dead. I then changed the alternator and now it won’t start. I’ve tried 3 different batteries in it, the big wire going to the starter has power going to it. But the little wire doesn’t seam to have power when turning the key switch.. Could it have done something with the sercurty to not start? Turn the key on. Lights, heater, windows. evErything works. Turn the key to start. And it doesn’t click or start. I’m puzzled as it was starting fine. It Just wasn’t charging. Plz help. lol.

 

First thing, check all your connections. it’s been a while since I replaced my alternator, but IIRC, there’s the one big cable that bolts on and then a smaller one towards the rear.

I don’t think it’s the security system. This sounds like a circuit isn’t complete somewhere. Clearly the things that are operating are getting power from the battery, but the starter isn’t, so that should help narrow it down.

I found that plugging your symptoms into ChatGPT is often helpful. I cut and pasted your message and here’s what it said, FWIW:

The issue you’re describing points to a starting circuit problem, potentially caused by something that occurred while replacing the alternator. Let’s break this down systematically:


1. Potential Causes:


A. Starter Circuit Issue

• The little wire going to the starter (starter solenoid wire) should receive power when you turn the key to the “Start” position. If it doesn’t:

• Check the starter relay or starter fuse. A blown relay or fuse can prevent power from reaching the starter solenoid.

• Inspect the neutral safety switch (or clutch safety switch if it’s a manual transmission). If this switch fails, the system won’t allow the starter to engage.

• Test the ignition switch. If the ignition switch isn’t sending power to the solenoid wire when in the “Start” position, it could be faulty.


B. Security System Issue

• Some vehicles’ immobilizer/security systems can disable the starter circuit if triggered. If this is the issue:

• Look for a flashing or steady security light on the dash when the key is in the “On” position. If present, the system may need to be reset.

• Perform a basic reset by disconnecting the battery for 15–30 minutes, reconnecting it, and trying again.

• Check your vehicle’s manual for specific security reset procedures (e.g., a key reprogramming sequence).


C. Wiring Issue

• Changing the alternator might have disturbed or damaged wiring:

• Inspect the wiring near the alternator and starter. Ensure all connections are tight, clean, and free of corrosion.

• Pay special attention to grounds. A bad ground connection can cause intermittent or complete failure of the starting circuit.


2. Steps to Diagnose and Fix:

1. Check Starter Relay and Fuse:

• Locate the starter relay and fuse (refer to the owner’s manual for location) and test them with a multimeter or by swapping them with known good ones.

2. Test the Solenoid Wire:

• Use a test light or multimeter to check if the small wire at the starter gets 12V when the key is turned to “Start.” If not, trace the issue back through the relay, ignition switch, or safety switch.

3. Inspect Grounds and Connections:

• Verify that all grounds are securely attached and free of corrosion, especially those around the engine block and battery.

4. Bypass the Security System (If Suspected):

• If the security light is flashing, consult your manual for a bypass or reset procedure. In some cases, you may need a professional to reprogram the system.

5. Manually Test the Starter:

• Jump the starter manually by running a jumper wire from the battery to the solenoid terminal. If the starter turns over, the problem lies in the ignition circuit, not the starter itself.


3. Likely Scenarios:

• If the security system has been triggered, a reset or reprogramming should resolve the issue.

• If no power is reaching the solenoid wire, the problem is likely in the relay, ignition switch, or wiring.

• If the starter works when jumped, focus on the starting circuit components.
—

Hope something here helps.

 

So today I put in another 8 hours of checking things out. I have full time power to pin 5 on the starter relay. If I jump it. It turns over. But doesn’t start.

I then went to the inside fuse panel. And the 7.5 starter fuse does not have power. With key on or trying to start. What would cause this ?


There is 2 7.5 starter fuses in the inside panel. The top one has power. The bottom one does not


Need help. About to light this thing on fire and call State Farm!

 

I’m still not getting this things. What’s the most common thing to fry the computer