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Helppp

Helppp 12/7/2017

1994 Dodge Dakota SLT 8 Cyl 5.20L

Brakes

Brake Light Switch...........

I was wondering if anybody can tell me how to check this switch/harness with an ohmmeter that I have......in other words..............I already have the switch off............but I don't know where to put my leads so that when I press the "button by hand".............what wires should be showing "activity" on my ohmmeter?
The "supposed best" wiring mechanic in my area told me to just spend the $ to buy another switch and see if it works : ( Not my idea of troubleshooting. .......
Thanks

13 Answers


HouseCallAuto

HouseCallAuto 12/7/2017

OK, there are two terminals on the brake switch. Set your meter with black lead plugged into ground and red lead at the ohms symbol (on my fluke 88 meter it is straight up center position) touch the leads together first as a test and see that the voltmeter instantly reads almost -0- (also known as continuity) then touch the two leads to the two terminals (you do not push the brake switch button) and if the switch is good you should get the same reading you just had when touching the leads together as a test. Pushing the button on the switch SHOULD SHUT OFF THE READING. Brake light switches work by having the brake pedal move away from the button when you press the brake pedal. If you have no continuity through the two terminals of the switch the switch is junk.

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HouseCallAuto

Helppp 12/7/2017

Whew..................I wish it was that easy............that kind of electrical problem I can handle. This brake light switch has 6 leads coming out of the switch to the pigtail.

HouseCallAuto

HouseCallAuto 12/7/2017

Okay I'll tell you which terminals in a little bit within the hour I have to bring up a picture of the connector first and identify the wire colors

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HouseCallAuto

HouseCallAuto 12/7/2017

The only two wires that matter for the test procedure I detailed are the Pink/Dark Blue and the White /Tan wire and remember, this switch already has a pigtail directly attached to the switch so the wire colors might only be seen at the connector that the pigtail plugs into. They might change color at that connector. Just note the colors that they connect to on the connector. Then you can do a continuity test on the switch. The rest of the wires function as a ECU input that the brake lights are on and for the cruise control cancel circuit. Just the two I mentioned are for the brake lights.

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Helppp

Helppp 12/7/2017


Thank you for the help. I'll give this a try tomorrow.

I really appreciate it ; ))

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Helppp

HouseCallAuto 12/7/2017

The Pink/Dark Blue should have battery voltage at all times and the White/Tan wire runs to the brake light sockets but not before going through the turn signal switch also and ultimately it becomes a ground after the bulbs.

Helppp

Helppp 12/8/2017

okay..............I might be getting myself confused here............and remember, I have the switch off, in front of my on my table..........

I actually can see the wire colors on both ends of the short harness..........switch end and plug end.
I have a solid blue............solid pink...........solid white.............solid black.........white with pink stripe, and yellow with reddish stripe.

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Helppp

HouseCallAuto 12/8/2017

Look at the wire colors where the connector at the end of the brake switch plugs into the vehicles' wiriing harness. You should see those colors I mentioned at that place.

Helppp

Helppp 12/11/2017

Whew......I've had a heck of a time getting back on this website...........seems like it was down ; (

Anyway............shouldn't I have to push the "plunger" on the switch to see if the switch is actually functioning......just like pushing the brake pedal?

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HouseCallAuto

HouseCallAuto 12/12/2017

No, the brake pedal normally rests against the plunger which means the switch provides "continuity" through the two wire colors when you are not pushing the plunger/switch and this is the same as your foot being on the brake pedal.. Said yet even another way...your meter should read continuity intil you push the plunger and then your reading should become an open circuit/no reading.

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Helppp

Helppp 12/13/2017

o.k.....I'm finally finding time to check this switch..........but as I read back over what we've said to each other, we are not talking about the same colors that are on this switch.

I have a solid blue............solid pink...........solid white.............solid black.........white with pink stripe, and yellow with reddish stripe, and you are referring to Pink/Dark Blue and the White /Tan ?

(Did I mention that wiring is not my strong suit) ? lololol

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HouseCallAuto

HouseCallAuto 12/13/2017

Yes, I know exactly what you said, but you need to understand that when I look at a wiring diagram, the colors of the wires on the diagram do not include the pigtail that is permanently affixed to the brake light switch. The wire colors that I told you about are there....I repeat...they are there....look at where the pigtail of the switch plugs into the vehicles wiring harness. You will see the colors I stated. Do not reference the colors in that switch wiring as they do not match.
I will say it another way...if you were putting the brake light switch back into your truck, you have to plug it into a connector. That connector has wiring going to it. The colors of the wires I mentioned are at that connector. I cannot explain it any other way.

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Helppp

Helppp 12/15/2017

Hmmmmm, I never mentioned that I have the "service manual" like a dealership would look at........it actually came with this vehicle. Unfortunately, I don't know enough to use the "electrical wiring diagrams" in it, but with your help, I was able to figure out what you were saying by process of elimination on the plug, as I looked at it on the diagram.
Here's the catch..........the two wires that you mention, (I've deduced from process of elimination again), are the middle connectors if you were holding the switch upright...........longest side up. I checked these two wires just as you said, although they are different colors than what the manual, and you, said should be there. The switch does exactly as you said................shows continuity until the plunger is depressed.
Thank you for your help..........(and what do you think about the different colored wires, by the way) ?

Anyway................now that this switch is out of the way.........let me tell you what happened to lead me to it in the first place.
My wife was pulling a pop up camper.......and apparently didn't have it all the way down on the ball. It came loose..........(thank goodness on our road where there is little to no traffic), and sheared the wiring harness that hooked into the truck harness. I spliced them all back together...........and had turn signals but no brake lights. So I checked the fuses.............and no fuse blown, (but actually replaced it with a new one anyway). Still no brake lights. Checked the bulbs............they show continuity............slid under and checked the rest of the wiring physically..............and nothing else was pulled/sheared/torn. Soooooo, the only other place I knew to go was to this switch.............which, thanks to you, we just eliminated.
Any ideas of where to go next?

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HouseCallAuto

HouseCallAuto 12/15/2017

Yeah, if I can make time tonight on my desktop computer I will give you a diagnostic strategy to follow. Understand that I am going on vacation tomorrow and tonight is my last hurrah to do anything for you for about a week but I will keep you in mind and I think I know what to give you to work with as far as a strategy goes. But you need to buy a test light - a 12-volt test light at the auto parts store for me to continue to assist, even if that means I assist you where I left off after I get back from vacation by let's say next weekend but that doesn't mean I won't try to write that strategy for you tonight

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Helppp

Helppp 12/15/2017

No............don't worry about it tonight........I have another vehicle I'm driving while I'm working on this. Have a great vacation...........and thanks for your help all this time. Hopefully, I'll talk with you when you get back ; ))

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HouseCallAuto

HouseCallAuto 12/15/2017

Access the stop light sockets left and right rear. You will see 3 wires going to each, The Brown/Light Green wire is the same circuit wire for the left and right socket and if you ground your test light lead and touch the pointed end of the test light to the contact in the light socket where this wire terminates it should illuminate your test light (12 volts) when you apply the brake pedal. This is for the brake lights. The Black/Yellow wire at the same socket should illuminate your test light when you turn on the parking lights. The 3rd wire (black) should be a ground at all times. To check for a ground just attach your test light lead to a good known 12 volt battery source, like the pos batt cable (I know you can't reach it) so improvise somehow, use any 12 volt source - even the parking light wire (Black/Yellow) and then touch the test light point to the black wire at the socket and the test light should illuminate to prove the ground. Let me know what you find.

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