15a fuse blowing... also won’t start.

[plcfcng]

The dome light works on a grounding circuit try unscrewing the dome light holder from the body there maybe a short there it's just a couple of screws also undo the rear dome light too infact do that one first
. What may also help is try using a circuit breaker instead of a fuse. circuit breakers cost a little more but when your working with a dead short it helps.

 

[brillo_76]

Mostly if you have a dead short. You can hook a light bulb of the same voltage of the circuit you working on in this case 12v across where the fuse goes. They go out when the short is gone and saves a pile of fuses being replaced for testing.

They also make a current tester that plugs into the fuse slot to measure the current flow.





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[plcfcng]

I used to put a car door buzzer in like this so you could hear it and not have to see it. I think a heavy duty car flasher would also work like this just only let it run for a few minutes at a time as they may get hot and burn out. While the dead short is still happening this will cause the flasher to click on and off quicker.
:hat:...

 

[brillo_76]

I used to put a car door buzzer in like this so you could hear it and not have to see it. I think a heavy duty car flasher would also work like this just only let it run for a few minutes at a time as they may get hot and burn out. While the dead short is still happening this will cause the flasher to click on and off quicker.
:hat:...

Yes I am sure that would work as well. anything that runs on 12v dc will work. Buzzers, Lights etc. Works only in a dead short scenario. Over current draw is a different situation as your exceeding the amperage and melting the fuse.

Being I haven't seen and amperage reading for across the fuse terminals. It could be either way. Most of the time it's dead shorts to ground.

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[phattyduck]

Okay so I've been studying the diagrams a bit. I've plugged back in the 1J connection.

I unplugged the 1F connection which controls the stereo, antenna, door switches. The new Dome fuse didn't blow. Now my personal lights work and my dome light will work in the Door position, but not the ON position.

Ok, that's good info. Now to track down what 1J and 1F have in common.

1J connector has:

1 - R-L, 10A GAUGE fuse power output (to alternator and other stuff)
2 - R, Headlight relay trigger signal (pulls to ground when switch is ON)
3 - L-W, Power in from HORN relay
4 - B, Power to horns from HORN relay
5 - empty
6 - G, Power from TAIL relay for integration relay and interior light power
7 - R-G, LH headlight low beam ground connection to headlight switch
8 - B-W, 7.5A IGN fuse power output
9 - R-G, RH headlight low beam ground connection to headlight switch
10- G-Y, Front RH turn signal power out
11- G-B, Front LH turn signal power out
12- L-Y, Power input from 15A DOME fuse to integration relay and other systems
13- empty

1F Connector has:

1 - B-W, Door switch inputs (front RH, rear RH)
2 - B-Y, 10A Gauge fuse output gauge cluster, etc
3 - R-G, low beam headlight ground through headlight switch
4 - R-G, signal to high beam indicator
5 - empty
6 - L-R, Power Relay output to power windows and sunroof
7 - G, tail light power output / interior illumination power output
8 - R, headlight relay trigger signal (pulls to ground with headlights on/flash)
9 - empty
10- empty
11- R, headlight relay trigger signal (pulls to ground with headlights on/flash)
12- L-Y, from DOME fuse to rear cargo light output, clock, ABS ECU, etc.
13- L-Y, from DOME fuse to cruise control ECU

Looks like the most likely culprits are the ABS ECU and the Cruise Control ECU at this point.

-Charlie

 

[Dieselchessy]

Back off on a tangent...….

In all this work have you opened and left open the back lift gate, or even opened and closed it at all?

Maybe check the inside rubber boot for the back lift gate wires. Check the back Dome light.

These are from a 98, so consider that.

 

[brillo_76]

Wonder if his EFI fuse is good?

You did solve the engine not running issue.

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[brillo_76]

Back off on a tangent...….



In all this work have you opened and left open the back lift gate, or even opened and closed it at all?



Maybe check the inside rubber boot for the back lift gate wires. Check the back Dome light.



These are from a 98, so consider that.

Excellent thought. That's always the first place I check when having wiring issues as the doors are notorious for having wires break and short as the age of vehicles increase. However dome does have power when the ignition off. That definitely could be a short under that tailgate boot causing the problem.

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[anormalflame]

Ok, that's good info. Now to track down what 1J and 1F have in common.

1J connector has:

1 - R-L, 10A GAUGE fuse power output (to alternator and other stuff)
2 - R, Headlight relay trigger signal (pulls to ground when switch is ON)
3 - L-W, Power in from HORN relay
4 - B, Power to horns from HORN relay
5 - empty
6 - G, Power from TAIL relay for integration relay and interior light power
7 - R-G, LH headlight low beam ground connection to headlight switch
8 - B-W, 7.5A IGN fuse power output
9 - R-G, RH headlight low beam ground connection to headlight switch
10- G-Y, Front RH turn signal power out
11- G-B, Front LH turn signal power out
12- L-Y, Power input from 15A DOME fuse to integration relay and other systems
13- empty

1F Connector has:

1 - B-W, Door switch inputs (front RH, rear RH)
2 - B-Y, 10A Gauge fuse output gauge cluster, etc
3 - R-G, low beam headlight ground through headlight switch
4 - R-G, signal to high beam indicator
5 - empty
6 - L-R, Power Relay output to power windows and sunroof
7 - G, tail light power output / interior illumination power output
8 - R, headlight relay trigger signal (pulls to ground with headlights on/flash)
9 - empty
10- empty
11- R, headlight relay trigger signal (pulls to ground with headlights on/flash)
12- L-Y, from DOME fuse to rear cargo light output, clock, ABS ECU, etc.
13- L-Y, from DOME fuse to cruise control ECU

Looks like the most likely culprits are the ABS ECU and the Cruise Control ECU at this point.

-Charlie

Had to take some time off from this due to work and a very pregnant wife. Gonna disconnect the CC ECU and the ABS ECU to see if that fixes it. I'll report back

 

[anormalflame]

Guys, I freaking did it! I figured it out.

I tried everything I could think of. I hit a wall. I tried the latest recommendations of pulling the plug on the ABS ECU and the Cruise Control ECU today. Tested both. Neither worked. I inspected the wiring boot at the back door. Saw nothing that looked irregular.

Then, finally, I saw the Antenna Relay near the cruise control ECU. I realized I hadn't tried it. I only disconnected the antenna under the fender and moved on once that did nothing. I pulled the plug of the Antenna Relay. Tested a fuse, and Voila! The fuse didn't blow! I tried turning on my dome lights. Both are working, but again, only when switched to DOOR. Still not sure about that one since they both worked when switched to ON before. But oh well. If you have any tips on that, I'd appreciate any help I can get.

What's working now

• Stereo
• Door Locks
• Dome lights (but only switched to DOOR)

My Turn Signals still aren't working, but I'm going to retest the fuses to see if that's the cause. If not, it's back to the drawing board combing the diagrams. Other than that, everything appears to be back to normal with the exception of the DOME lights not working when switched to ON.

Thanks for all your help guys! Again, this was interesting and educational. I learned a lot about the electrical system in my rig, and I'm sure Uncle G would be proud.

 

[anormalflame]

Aaaaand by some miracle the dome lights are working as they should. And I swapped the turn signal fuse although it didn't appear to be blown, and now the turn signals work. All is well now. :dancin:

Off to swap the valve cover gasket next. Parts ordered. Second time doing it on a 4Runner so it should be a piece of cake.

Thanks again guys!

 

[anormalflame]

[MENTION=10169]TheDurk[/MENTION] [MENTION=466411]Dieselchessy[/MENTION] [MENTION=163346]plcfcng[/MENTION] [MENTION=221666]Joelzy[/MENTION] [MENTION=67746]Brentif[/MENTION] [MENTION=50279]spartacus[/MENTION] [MENTION=138935]catrains[/MENTION]

Thanks for the help guys. Not sure if you saw my post about what it ended up being, but it was the antenna relay. You can read above for the breakdown.

 

[catrains]

relay has a diode DC . so the diode shorted out when the jumper cables were put on reverse.

good you did the work ... electrical work on vehicles is a person that throws parts at it.. you did a very good job.............................

 

[TheDurk]

Aaaaand by some miracle the dome lights are working as they should. And I swapped the turn signal fuse although it didn't appear to be blown, and now the turn signals work. All is well now. :dancin:

Off to swap the valve cover gasket next. Parts ordered. Second time doing it on a 4Runner so it should be a piece of cake.

Thanks again guys!

Just to beat the horse that won't die, you can't tell a bad fuse by LOOKING at it. Test with a test light or meter or swap a known good fuse.

Good job. There are a lot of relays, and not all of them have diodes. I would love a list of the ones that do.

 

[brillo_76]

Glad to see you got it all figured out. I knew the users would get you fixed up. Look at all you learned.

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[Dieselchessy]

Cool that you got it fixed. You did some good work chasing that down.

 

[Cnellis80]

I've been using these threads where people are trying to figure out the dome circuit. I made it to unplugging 3C and the beep went away, after 1e, 1a, 1f testing. After unplugging 3c and continuity being disrupted, what do I do next? I'm sorry if it was mentioned somewhere previously, but after hours of searching I'm unable to find it.

I have a DMM, a fair amount of electrical knowledge, and a test light that I'm not sure I've ever used. I bought a 2000 4runner limited 4x4 and it has some electrical gremlins in this circuit. I have the FSM for my vehicle, but didn't see a pinout anywhere in it.

Thanks in advance for the help!

 

[TheDurk]

I've been using these threads where people are trying to figure out the dome circuit. I made it to unplugging 3C and the beep went away, after 1e, 1a, 1f testing. After unplugging 3c and continuity being disrupted, what do I do next? I'm sorry if it was mentioned somewhere previously, but after hours of searching I'm unable to find it.

I have a DMM, a fair amount of electrical knowledge, and a test light that I'm not sure I've ever used. I bought a 2000 4runner limited 4x4 and it has some electrical gremlins in this circuit. I have the FSM for my vehicle, but didn't see a pinout anywhere in it.

Thanks in advance for the help!

Test each pin on the 3C plug for continuity. When I know what pin carries the short, I can go circuit by circuit to see where it goes. There is no easy list. Two I found are 10 is key light and 7 is rear dome. Note the wire color to double confirm. 7 and 10 are both blue-yellow. Page 27 shows all the module does is connect Pins 4 through 10 to each other.

To get the numbers, see pin out on page 26 here. Concentrate on pins 4 through 10, excluding Pin 8, which is the incoming from 1f that feeds 4 through 10, which should show 12V+ full-time if battery is connected and DOME fuse intact:

 

[Cnellis80]

I hadn't realized that you responded to my comment/post yet. I apologize for the late reply, and want to thank you for your response.

I have made it a point to look for you and IBallEngineer when searching this forum, as you two seem to really lay things out and know what you're talking about. Since my comment a few days ago, I've narrowed the pin on 3C to terminal 7- blue with yellow. Since snipping that wire, no more blown dome fuse. I've been looking at the EWDs and have yet to figure out what that wire controls.I see you stated in your response that it controls the rear dome light.

I actually started going down the list of everything you mentioned in another post about what is on the dome circuit, unplugged everything mentioned including the rear dome and powered it off, still had the same problem. Clipping the L-Y wire on plug 3C terminal 7 seems to have "fixed" the fuse blowing, but hasn't helped with rectifying the cause lol.

I'm actually in the process of using a thread you and IBallengineer are on regarding 2000 4runners and the lovely DRL nightmare. I bought this 4runner earlier this month (have always wanted one) and it had a few issues. I was wondering why the headlights left a lot to be desired and have figured out why...they're stuck on DRL. I am down to seeing if it's something to do with the combo meter now, tried all the other troubleshooting y'all had mentioned. I plan on going out shortly and checking.

I love that this forum has helped me with repairs and chasing electrical gremlins!! I will say, there's nothing worse than seeing a request for help, someone writing out a very detailed reply of troubleshooting tips, then the original post ghosts with no results. I will be sure to NOT be "that gal".

Thanks again

P.S. I always put a meter on fuses to check for continuity, never rely on how they look when pulled from the fuse panel.

 

[Cnellis80]

Test each pin on the 3C plug for continuity. When I know what pin carries the short, I can go circuit by circuit to see where it goes. There is no easy list. Two I found are 10 is key light and 7 is rear dome. Note the wire color to double confirm. 7 and 10 are both blue-yellow. Page 27 shows all the module does is connect Pins 4 through 10 to each other.

To get the numbers, see pin out on page 26 here. Concentrate on pins 4 through 10, excluding Pin 8, which is the incoming from 1f that feeds 4 through 10, which should show 12V+ full-time if battery is connected and DOME fuse intact:

Thank you!! Long reply (couldn't find how to quote lol) listed above this one. I've interacted in forums before, but mostly just read. Since I plan on keeping my 4runner forever, and doing all repairs myself, I look forward to interacting in this forum. Thanks again!