I have a problem that's driving me nuts

There is no power going to the starter relay through - activation circuit to the starter. Ignition switch sends power to starter relay but there's no power available at relay to send through to starter! Does anyone know where it picks up power????

FYI my dad jumped multiple points of starter relay socket that ended up frying the five amp fuse when we replace the 5 amp fuse it started for about a week but now it doesn't start again. Did we jolt the power or something

UPDATE***** jumping starter piun does nothing again!?!? damn

 

Welcome aboard sir. When did this problem start? Any other information that would help? You check the under hood fuses and ground wires?

 

You'll have to do some digging, but you'll find your answer here

• 2002 Tundra EWD - EWD468U
  • Includes all sections in the original book
  • 273 pages

@VR6T will get a kick out of your user name

 

Do you or did did a previous owner install/remove an alarm system at any point in the truck's life? If they did, it would be sitting up under the dash between the ignition and the engine bay, and that's the first place I'd be checking.

Seriously, alarms may have a shelf life of 8-10 years if you're lucky and some dealers quietly installed them for an upcharge, we've seen trucks with SECURIKEY+ and KARR brand systems installed by the dealer plenty of times on here.

And dummy check: Did you check all fuses under the hood and in the dash? Did you check for the far-too-common case of water getting into the fuse box from the a-pillar, a cracked windshield, or sometimes from abad windshield install or rusty surround?

 

What fuses under the dash? The 5amp ignition fuse is good and gets power in start position

 

I have been dealing with starting issues myself recently, so can ask about things I've been diagnosing.

Have you tested your starter relay for proper functionality? You mentioned that the ignition sends power to the relay, but then no power from relay to starter. As I understand it, power for starter is directly connected to the positive battery terminal and once the ignition sends signal to relay, it closes the circuit and then the starter motor will go, among other things like signaling the fuel pump to go as well.

 

This is my general understanding as well, but I want to say with the starter relay, the ECU is triggering ground across the relay, if all expected conditions are met? Assuming the signal is getting where it needs to go.

While I'm sure the FSM would be helpful here - and there's a link to it in the 'So you just bought a 1st Gen' megathread - I usually like to hand off this video for basic troubleshooting, and it should appli to @VWmanwithTundra's truck:

https://www.youtube.com/watch?v=0jWouSQYTnU​

 

PS - it's probably NOT the starter, it's almost always never the starter, but you should inspect carefully between the runners of the intake for evidence of mice nesting underneath it also, since they like to get under there and chew up wires, to the starter, knock sensor, and SAI pump for later years.

If you remove the intake for any reason ONLY USE OEM GASKET to replace the intake gasket (and do replace it, or you may be lifting the intake again soon due to intake manifold leak)! We have a bunch of pictures of aftermarket gaskets, and they seem to last for about 6-12 months on average. Just cough up the money for OEM.

And if you do decide to replace the starter - even though it seems like lack of power delivery is the issue - only use Denso brand. They're the OEM. Get the cold weather version. It should last another 15-20 years. Experience on here from dozens of people is the parts-store brands only last 2-5yrs max.

 

Am1 isn't getting constant power*

 

According to the video Shifty posted, AM1 provides constant power to the starter relay. If AM1 is not getting constant power, seems like you'll need to diagnose a short or open in the electricity upstream of AM1.

I'm assuming you already tried this, but just for a sanity check, can you jump the terminals of the starter relay plug (5 and 3) and start the truck that way, with the key in the ON position?

 

Well, if we go by that video, I guess you'd want to check for power at the connector at the body of the Neutral Safety Switch ("NSS") when someone is turning the key forward. If you get no power there, you need to be inspecting the wiring between the dash 5A fuse and the NSS. Noting that it's super fucking common for window/a-pillar leaks to get into the in-dash fusebox and fuck up the circuitry inside. How common? (pics & pics & pics, it happens a LOT). If that happens, you might get really sporadic/squirrely results out of starting. Reminder: It's happened a LOT. If you have a cracked windshield, live in the rust belt, had your window replaced, or your a-pillar seals behind the windshield trim are old, these could all lend to that leak!

If you have voltage at the NSS, based on the video, you'll next want to check for voltage here, and if nothing, you've got a problem with your Neutral Safety Switch. However, you should also check for voltage at the RED socket (12 o'clock position) to confirm the starter can even get power when the relay is energized. Furthermore, you should try sending power into the BLUE socket (6 o'clock position) to see if the starter turns over. These are all things I would try, at least, per the video.

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Am1 fuse isn't getting power but the 5amp dash fuse is at cranking position

 

No the am1 isn't getting power! Do you know where it gets power from?

 

It started all of a sudden I don't know how it started. I replaced the ground wire check the positive check the relay what it is there is no power getting to the am1 fuse but I don't know where it gets as power from it seems like the alternator but it's all in the harness so I do not know I have no idea

 

We've seen corrosion inside the cables like this cause meltdowns up under the engine bay fusebox, and burn up the legs on fuses like this, BEFORE the fuse died, breaking the circuit. There's not a lot to it, I think you have one lead from the battery up into the bottom of the fusebox, and I think one from the alt-up - which, take your time and be patient pulling the box to get inside, it can be tedious! Don't quote me on the two leads going up in there, I'd hafta look at my '06 and hope it matches your '02.

Again, wiring diagrams are in this thread near the top, linked in the 4th or 5th paragraph with other stuff. It should help you figure out the path up to AM1 for your year/cab.

 

I've been a mechanic for over 20 years and I am so confused where on this diagram is the starter and what is supposed to have power and when is it supposed to have power?

 

I am confusing myself I swear so when you turn the key to activate the starter. Where is the power coming into the starter and where is it going to the starter through the relay?

 

Because a normal relay should be powered all the time have a ground on the activation side and then the ignition starting position would send a power to the positive side of the activation circuit inside that relay but it seems like Toyota is completely different

 

Are you supposed to be able to jump the starter relay and get it to start with the key off?

 

This video should help for '00-'02, and possibly later years.

https://www.youtube.com/watch?v=0jWouSQYTnU​

 

no it doesnt help

 

it doesnt say anything about what if the am1 fuse doesnt get power

 

i dont see it on the diagram sir

 

the GD am1 fuse gets power but not the relay!!!!!!!!!!! wtf its not on the diagram wtf!!!

 

My fusebox won't be the same as your fusebox. Care to take a pic of your fusebox with the lid upside down showing the legend so I can ballpark where yours is? (Disregard that, now you're saying AM1 is getting power, just not the relay)

Did you put any effort into pulling the AM1 fuse and throwing a meter on the legs, or unmounting and physically looking under the fusebox for stuff like this, like I linked above that was causing no-charge situation for that member? Since fuses don't always pop, especially if you have corrosion inside your cables, which these trucks are pretty well known for developing?

The AM1 fuse and all the wiring linking this stuff is under your fusebox itself. It's time to carefully, patiently pull the fusebox and look under it IMHO.

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ok so why isnt the am1 fuse in the diagram?

 

its not the fusebox! am1 fuse power leaves the fusebox and goes who knows where and then returns where it splices and powers the relay

 

Lot of yelling here from the person who needs help. Maybe take 5 and regroup.

 

Likely you just lost your best source of info on here...

 

diagram is confusing