No Brake Lights! Please help.

Vexarana · Nov 29, 2015

Hey all,

So my trusty Ranger is confusing me.

I noticed in the past few days that I do not have brake lights when pressing on the pedal. Troubleshooting steps I have done are as follows:

Replace brake switch.
Replace both bulbs on each side.
If you put hazards on, they flash.
If tail lights are on and hazards are on, STILL flash.

I'm pretty lost here. I even tried checking with the truck running to see if I needed to press harder on the pedal, but nothing happened still.

Tl;dr:
Have power to rears.
Hazards will flash stoplights.
Brake pedal doesn't. Replaced switch. Still doesn't.

enjr44 · Nov 30, 2015

Troubleshoot using this from the tech section.

http://www.therangerstation.com/tech_library/EDiagrams/files/Diagram_turn_stop_hazard.JPG

Vexarana · Nov 30, 2015

What do the LG and LG/ R H mean? Fuse Block 1 means that would be the Fuse #1 in the block right under the dash right? Which also feeds hazards?

So that means.. Either wire 10, or wire 511 is bad? And I just need to test to see if the wire 10 is hot (which it should be all the time) and make sure that wire 511 gets hot when you press on the brakes?

I don't have a multi-meter. Is there a cheap way to test whether these are hot when I get home?

Spott · Nov 30, 2015

LG means Light Green, LG/R means Light Green with Red stripe.

A cheap way to test is to get a cheap multi-meter (about $15) from the hardware store. You could get a test lamp that's a little cheaper, but it's not good at indicating whether you have a low voltage, and a multi-meter can do so much more, so just buy the meter. It can be very useful in the future.

enjr44 · Nov 30, 2015

Come on guy you need to help yourself a little here. Your profile says your active duty. Get some help from one of your comm guys.

Light Green and Light Green with red hash marks. Make a test light using a bulb and a couple of wires.

Vexarana · Nov 30, 2015

Lol unfortunately the only Comm guys I know are radio and seem to be scared of in depth electronics stuff. Does it matter if I get a cheap multi-meter? I know Fluke is good but that $$$

enjr44 · Nov 30, 2015

OK, I don't know where you are located. I do know that almost all bases/posts have an auto hobby shop (think they call them skill centers now) and a motor pool. Those guys at the hobby shops know a lot and the pool guys would almost always rather work on your truck than what they are supposed to be doing. And there is almost always someone hanging around that isn't doing anything useful and will give you a few minutes. So go talk to them. Since you have the wiring diagram, they will help you figure it out. Maybe even loan you a meter.

And, yes, the 6 dollar meter at harbor freight will work just fine for what you are doing.
http://www.harborfreight.com/catalogsearch/result?q=miultimeter

Vexarana · Nov 30, 2015

Unfortunately, I am in PME right now and our base is too small to have an auto hobby shop open later than my duty hours. I'll try to pick up a multimeter on the way home and just test it myself tonight.

One thing someone suggested was that it might be the fuse in the engine bay, but looking at the diagrams, if that was a problem there, I would not have hazards because that runs off the same dash fuse right??

Vexarana · Nov 30, 2015

Update:

I got a multi-meter and pulled the clip harness off the brake switch. When testing between the two terminals, it is reading in the 0.00X mV range. So basically zero. The wires are sheathed up. Where can I find the other end of the other end of the Light Green w/ Red wire? The diagram shows it going to the fuse box. So it connects there? There's just so many.

Anyways, I will keep seeing if I can figure out where TF it is at. If I find anything else I will post it here.

Thanks so much for the help enjr44!

Edit: So it looks like the LG/R wire goes into the flasher?? I have a HD flasher unit in there. Could that be causing any issues?

Edit 2: So I got a photo of the LG/R wire and it looks like it goes right under the flasher and is crimped to something. But without the flasher in there, how can I test if this is getting proper power??

Picture of what I am looking at

adsm08 · Nov 30, 2015

Grab your Comm man and tell him to stop being a pansy ass. Nothing on your truck comes close to counting as "advanced electronics". Certainly nothing in the brake system.

What I would do at this point is follow the power. Get your meter, get a jumper lead, any piece of wire long enough will do. Run your jumper to the battery negative, and make sure you have power coming into the brake switch. Then go on down the line. I have the diagrams for that truck at my other house. If I'm not too out of it when I get there tomorrow I'll grab the book and trace out the rest of the circuit.

Most of the time a problem like this is in the multi-function switch. The brake light circuit passes through there.

Vexarana · Nov 30, 2015

I did just replace the multi function switch a few months ago because my turn signals stopped working. I could pull it apart and spray some contact cleaner on stuff and then throw some dielectric grease in it.

As far as jumper wire.. Is that just a super long wire? Something that I can have attached to the battery and still work in the cab? I had been probing with the red on whatever circuit I was testing and the black on the firewall behind everything.

Do I need to retest everything?

Edit: Looking at some presentation online and my Multimeter manual. It says to test voltage I need to have 2 points on the circuit in series??

Positive power (+V) comes from the + on the battery... so in order to test if a wire is hot or not, I need to connect the black lead to the negative battery terminal (-V)??. But if the battery is +12V wouldn't a chassis ground still read the proper voltage?

Spott · Nov 30, 2015

If your ground connections are good (and sometimes they aren't), then chassis ground will work for testing, because the chassis is hooked to the -V battery terminal. A convenient point to connect to ground is the outside shell of the cigarette lighter socket.

Vexarana · Dec 2, 2015

Could a bad chassis ground be causing this? Where would I find those on the truck?

enjr44 · Dec 2, 2015

Vexarana said:
Could a bad chassis ground be causing this? Where would I find those on the truck?

No, look at the wiring diagram. All the rear lights tail, stop and hazard use the same ground. Since the hazaed lights work you know the wires from the multifunction switch to the bulbs and then to ground are good. You also know that the mulifunction switch is probably good because, again, the haz lights work.

You have to trace the voltage from the fuse to the lights. Start at the fuse. The only way to do this is to stop jumping around and symptomatically go from one point on the diagram to the next.

Example, is there 12vDC at both sides of the fuse and are both wires coming out of it connected? Next is there 12vDC at the stop light switch? Then you have to check that when you push on the brake peddle you get voltage out of that switch. Next, is the voltage getting to the mutifunction sw??

Read the diagram or get some help in reading it and follow it like the wires were water pipes and each connection is a place where the pipe could be broken and no water is getting to the next place!!! Switches are like shutoff valves/faucets where you can turn the water on and off.

jeremysdad · Dec 2, 2015

Re: Are the bulbs in teh sockets 3156 instead of 3157?

No Brake Lights! Please help.

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