Electrical Problems

Hello, I was referred to this site because of the electrical issues that I am having on my 2001 Tundra 2WD SR5.

I had to replace both the battery and alternator. So to begin with of course there is a new battery and the 100 amp alternator. It was running smooth with no issues. I stopped to put gas and when I went to turn the truck back on, only certain electrical systems were working.

WORKING:
Truck turns on and drives.
All around lights turn on.
Dome light, interior lights.
Horn.

NOT WORKING:
Turn signals.
Radio.
Emergency Flashers.
Gauges or lights to dashboard gauges.
Cigarette lighter sockets.
A/C or heater.
Windows do not roll down..

I of course checked all of the fuses on the interior and engine fuse boxes. I checked continuity on all of the fuses and cleaned the pins. I checked the relays as well. No fuses were blown inside of either box. I did not install the alternator with the battery connected. It sits in a garage so there are no rodent issues or any loose or shorted wires. I can't figure this issue out. Can anyone help in this matter? Thank you.

 

Is it an intermittent problem or did it just quit one day and have never come back on?

I have a 2005 F150 and for whatever reason the main power to the dash comes in through the interment cluster. About once every 3 weeks I turn the key on and the entire dash is dead. No gauges, no radio, no ac ect. I isolated the problem to the connector in the top of the cluster. If I pop it off, plug it back in everything comes back alive. It seems to be more frequent when hot. I need to quit dragging my feet fixing it but anyway.

If your problem is intermittent it will be harder to find. If everything just stopped working and hasn’t come back on yet that could be easier to isolate.

When I get a minute I will look at the Gen 1 wiring diagram and try to see potential places for issues.

 

Thank you for your response. It is not intermittent. It just went off and stayed off. I never had this issue before. I am still trying to chase the issue down and have no luck. I was lucky to drive it home. Thanks for your help.

 

Do you believe the problem is a result of the battery and alternator install? Like you installed them and then it quit working shortly after?

Just want to clarify the alternator and battery were installed prior to the problem and not in an attempt to fix the issue

 

This did happen after the battery and alternator install. The alternator went bad and the battery was old. I swapped them both out. I did not have this issue before the ALT went bad. Both are brand new and installed properly. This was NOT an attempt to fix the issue. Thank you.

 

Is the alternator charging?

 

Yes, at the time I checked it, it did. I will go back out and verify again.

 

I think your 120A ALT fuse is bad. If you see the Red arrow I drew in this photo, if the fuse is bad the entire top half of the circuit (everything in the red box) will not have power.

Things inside the Red box that would not have power if the 120A ALT fuse was bad
Power Outlets
Alternator Charging
AC/Heater
Fog Lights
Ac Panel, Radio, 4WD ect
Power Window
Turn Signals / Flashers
Gauges

Check the 120A ALT fuse and make sure it has voltage on both sides.



Look here

 

Need to figure out if it is supply or ground. If you can get to the back of the cigarette lighter. see if you have voltage at that point. If you do, you have a ground issue. Alternatively you could provide a good ground (i.e. separate wire) to the cigarette lighter and see if it fires up. Would suggest you get a wiring diagram and look at the things that aren't working and see if there is a common ground or a junction through which all of the voltage supply flows to these items.

 

I would also double check any of the ground connections that you may have took loose or moved. I looked real quick at the wire diagram but am having trouble narrowing down what all the circuits that are not working share.

 

Since you said you tried all the fuses, I'd look at a possible ground issue. Like @Buckaroo stated, simply run a jumper ground wire to one of the accessories you said was out and see if you get them to come on.

 

I thought about this a little more and am still convinced ALT fuse is the place to start.

While it could be a bad ground, in my experience grounds create more of an intermittent issue that eventually fails all the way. They get dirty/corroded over time. The only way a bad ground instantly kills an electrical system is if it’s unbolted or cut. I also don’t see it likely that one broken ground point kills half the truck.

I could however easily believe a brand new alternator on its 3rd or 4th start had a power surge as you turn the key leaving the gas station. One that would blow the 120a fuse or another main fuse in that circuit.

 

Thank you for the diagram and pointing out what is in the red box. I will just change it out for a new fuse.

 

Thank you @jeff 5_7 for the diagram and for pointing out what could be the issue. This helps out so much. I will change out that fuse for a new one. It won't hurt.

@Buckaroo, I will test the back of the socket to see if I have voltage there. This will help point out if i have a ground issue.

@Huntrtn, I am chasing down the ground issue as you indicated and I may just put in a new battery ground cable. I will clean whatever ground i can find.

@texasrho83 - Yes, thank you. I am trying the advice given to see what I can find.

@Jeff_5_7 - You have a good point. Maybe there was a surge and I was hoping to find some blown fuses. I am testing the alternator to see if it is charging. I will change out the 120 fuse. When I went to purchase the alternator, there was a difference between a 75 and 100 amp. The guy indicated that it would be a 100 amp for the extended V8 cab. If it was a 6 cylinder then he would go with the 75 amp. Since there is a built in regulator, I figure it would not hurt anything with the 100 amp. I am going back outside to see what I can find.

Thank you all for your help so far.

 

You should be able to quickly look at the fuse and tell if it’s still good.

Let’s us know what you find and we will go from there.

Just found this. Guy had a very similar problem and had just changed the alternator. His 120A fuse was blown. A photo in the tread shows it’s location in detail https://www.tundras.com/threads/multiple-electrical-issues-first-gen-2001-toyota-tundra.55552/

 

This is one annoying thing about the forum is that you posted in a great place under electrical the bad thing is most of the regular 1st gen guys won't see it. I linked your thread in a first gen specific thread to get some more eyes on it hopefully.

 

I blew my 120 in the '02 Tundra futzing with the alternator (removing the cable without disconnecting the battery and then poof shorting to chassis)

All signs point there. It's a mild pain to unbolt things to get it out, give yourself adequate time, it's not a plug/unplug but terminals are bolted in from the sides so you have to unbolt the entire fuse box to get it up to where you can access the bolts.

If your alternator is 150 amp you might want to put a 150 instead of the 120.

Also it was hard to see if the fuse was blown until I destroyed it removing. Not super obvious to read those things. But my scangauge clearly showed 12v rather than 13+ with ignition on.

EDIT: Just re-read, you went with a 100 so 120 should be good but just for completeness, the 140 I have is 90982-08286, though I ordered it after swapping in a generic 120 from Napa and haven't swapped.

 

ALT fuse is where I'd start, and if that doesn't fix it, I'd flip the underside of the engine bay fuse/relay box to look for shorts. Take your time, removal isn't a breeze.

You don't want to be this guy I helped over in the 1st Gen forum. Note that his ALT fuse wasn't blown. If you're interested in the details/symptoms, scroll to the start of his thread.

 

Replacing the alternator fuse is time consuming and a bit frustrating but not terribly challenging even without prior experience. I’m not a mechanic by any stretch. I watched some YouTube’s but it’s really a matter of completely disconnecting the battery, unbolting then fuse box, and then pressing tabs in until the bottom comes up. That gives access to the bolts. Swap, snap back down, replace mounting bolts.

I probably spent a couple of hours but it could be done in 15 minutes if you’ve done it before. I’d rate it at 60 minutes for a reasonably careful normal human doing their first attempt.

 

While 120A ALT is a good start, some of your lost functions are not part of 120A ALT.
Hopefully you have an VOM(volt ohm meter) not only for voltage checks but continuity checks searching for possible open grounds.

From 2001 EWD....

 

This is not correct.

NOT WORKING:
Turn signals....20A HORN
Radio....15A DOME
Emergency Flashers....20A HORN
Gauges or lights to dashboard gauges....15A DOME
Cigarette lighter sockets....15A POWER OUTLET1 and/or 15A POWER OUTLET2
A/C or heater.
Windows do not roll down....30A POWER

Turn Signals get constant power from 20A Horn, but the 5A Turn fuse is responsible for powering the flasher relay as the key comes on to enable the blinkers to work.
Radio gets constant battery power for memory ect from 15A Dome, however the 15A ACC fuse is responsible for powering the radio up as the key is turned on.
Emergency Flashers Same thing as blinkers, the 5A Turn fuse wakes the flasher relay up when the key comes on. It is power with ingition/rotating the key.
Gauges and Dash Lights are powered by the 10A Gauge Fuse. Dome fuse only runs the door ajar indicator light and the key cylinder right light.
Cigaretter Lighter: 15A ACC fuse powers the relay which then goes through the 15A Power Outlet1 and 15A Power Outlet2 Fuses.
A/C / Heater: 10A Gauge powers the AC control panel and the heater relay.
Power Windows: 5A ECU IG fuse wakes up the integeration realy when keys comes on to allow the windows to operate.

If you look closely you will see literally every system he has failing ties back to the 120A ALT fuse. All of these in my list in bold are in the red box above I made on post #8. I am 99% sure his only issue is a bad 120A ALT fuse. Replace that and it will fix everything. Just waiting for @mrfastback to report his findings.

 

Info shared came from 2001 EWD....I'll just leave it at that....OKI DOKI ?

 

Yes and you misinterpreted the EWD. If you just look at the J Power Source Tables listing all the fuses, it gives very generic listing of the system they belong too. You have to go look at the actual diagram for the specific circuit to understand what is really happening and how it works. I dont want him chasing around ground wires and other fuses becasue some one here gave him bad advice.

For example the Radio and Integration Control Panel (AC control Panel)

The 15A Dome fuse is powered by the battery 24/7, it goes into the intergration control panel and then to the radio. Its only reason for being there is retaining the memory in the modules when the key is off. Your radios clock, preprogrammed radio stations ect. The stuff you loose when you completly unhook the battery.

The 15A ACC fuse is wired directly to the ingition witch, as the key comes on it is powerd and then sends electrcitly to the intergration panel and radio to power them on.

Almost all of these "Key On" power signals are supplied by the 120A ALT fuse and are wired inline with the ingition switch. All of his systems that broken at not getting a power signal as the key comes on becasue the 120A ALT fuse is bad.