No power to Stop fuse underhood fuse box

After checking fuses, light bulbs and replacing brake light switch I pulled the stop/brake light fuse and tested if I was getting power to the stop fuse box location, none. Blinkers work, taillights work, no other electrical issue except in line fuse to accessory/cigarette lighter blown due to an air compressor overload.
I'm out of ideas short of running a hot wire from brake light switch to a powered location in the fuse box. Running down a short sounds like a PITA. Has this happened to anyone?
Thanks

Jim

 

You're checking with one probe on negative battery terminal and the other on the fuse contacts?

There shouldn't be much wire from the battery to the fuse box. Maybe unbolt the fuse box and check the wiring.

Also, maybe there is a fusible link upstream from the fuse box, like near the battery. A blown fusible link would probably affect other circuits, so this is a long shot.

 

You don`t have a short!! You have a open circuit.

If you had a Short circuit protection would be open or your truck would be a smoldering pile being hosed down by the Fire Department .

The brake light circuit should be powered off the alternator fuse but yours might be different.

 

I agree with this. Here is the wiring diagrams for both the 4 and 6 cylinders. The brake light circuit is on the sides and top of each diagram.

 

The alternator fuse only powers the stop/brake fuse? If the alternator fuse was bad wouldn't other fuses in the fuse box not have power also? Everything else works fine, only the stop fuse is not hot.

 

No the Alternator fuse is the source of the buss that feeds several fuses .

If your fuse for the brake lights is not getting voltage it is open between the Alternator fuse and the brake light fuse right under the fuse block.

Just how are you measuring Voltage at the Brake light fuse ??

Corroded fuse block ??

If you do decide to run another wire rather then fix the problem install the correct circuit protection

 

It is hard to diagnose your particular problem with no pictures, no details on performed actions so far (how did you check that fuse doesn't have power?). But factory diagrams might help identifying parts and how stuff should be connected.





The 7.5A ALT-S fuse is just next to STOP fuse. If one has power the other doesn't the problem is just inside the fuse holder itself. The red arrow points to ALT-S fuse (just below STOP fuse)

 

Thank you for the replies. The diagrams are most helpful. Rysiu, I do NOT have power to that fuse when measuring using a multi meter w/negative probe on neg battery post and positive probe to the ALT-S fuse post (I pulled the fuse). There is no power with the engine running or not. The alternator is charging the battery ~13.6 volts
I do have power to the dome fuse location using the same method.

 

What about tail relay? Does it have power?

 

He said stop fuse, which is for the brake lamps. The tail light relay feeds the lights that came on with the headlights. Same bulb different filament. The taillight relay doesn't have anything to do with the Brake lights.

The stop fuse and taillight relay have nothing to do with each other. Stop lamps are brake lights, and tail lights are what come on with the headlights.

I would be sure that I was in fact checking both terminals in the stop fuse slots. Then, check the alt fuse, but really if everything else is working, that fuse is fine.

 

Yes they are different circuits but if you look the tail light relay is getting Voltage from the same Power Source .

I would ask the same question trying to figure out just where the open circuit is

 

^This

He said: Stop fuse doesn't receive a power. Also ALT-S doesn't have power either.

If the 80A ALT fuse is bad, the truck wouldn't even start. He said "The alternator is charging the battery ~13.6 volts" so obviously the truck is running.

 

This is to much like work!!!

 

So to clarify: You do not have +12V (measured between probe and battery negative) when you touch the probe to either side of STOP fuse holder. Same thing when you touch the probe to either side of ALT-S fuse holder?

What I see strange the ALT-S fuse is used to power IC Regulator in car's Generator, and without that the generator would not charge the battery (don't look at charging light on the dash, as if it might not show the correct status when IC Regulator is not working). It is possible that some contacts are rusted and your probe is not making good contact while testing. It is better to be sure about the diagnostics instead of finding something simple stupid thing but after tearing all stuff apart.

 

You are right, after taking a small file and cleaning the slot for the ALT-S fuse location I'm getting voltage. However that did not work for the Stop fuse.
I'm pulling the fuse box and checking underneath for a loose or broken connection.
I really appreciate the responses.

Jim

 

Unless you had Rodents or Gremlins chewing wires .

Lots of Corrosion under the fuse block .

Hard to think how a open circuit would happen.

Best of Luck !!

Please let us know how this plays out.

 

With pictures please. Because

 

I have a 1995 toyota tacoma, no dash lights no cranking, headlights work and key chime works. No power on fuse box inside truck power on half of fuse box under hood. The ALT 80 amp fuse was bad. The power i was reading on half the fuse box was feed back through other systems in the truck. Pull that fuse or the top off of it and check both sides of it. If you show power on either side then read across the fuse. If you read power across the fuse it is bad.