RylandB96

Howdy folks,
Stock 1996 Country.The factory fogs haven't worked since buying it.

Replaced the bulbs, cleaned ground contacts and connection with a wire wheel in the lamp housing, connections look good, and the relay up front sounds like it clicks on and off when I flip the switch in the dash.
However, the brights don't switch to low beam when the fog switch is on, (I believe they should, whether the fogs work or not?) and the switch light itself does not work, (Pulled the face off the switch and it doesn't look fried to me though)

So are there a couple things potentially wrong here or am I missing a simple answer? Thanks

Turbo X_J

Just because the relay clicks doesn't mean it's good.

RylandB96

Thanks,
Tested relay today with a multi meter. No resistance with power source applied. The resistance on the coil side of the circuit, (pin 86 and 85) was ~65ohms which is normal, correct? I've never worked with wiring/electrical before so I'd like to solve this one.
Anyway, the relay checked out fine as far as my knowledge permits. So shouldn't the brights switch to low beams when the fogs are turned on with a properly functioning relay...? (They do not)

BlueRidgeMark

So, you have two problems to solve?

1. Fog lights don't come on when the switch is turned on.
2. High beams don't switch to low beams when the fog light switch is turned on.

Did I get that right?


I've never messed with the factory fogs on a Jeep before, so take this with a grain of salt, but I've never heard of high beams being switched to low by turning on fog lights. I HAVE heard of the other way around, though.

If your understanding is correct, then there must be a connection to the headlight relay from the fog light switch. Possibly through another relay. You'll need to get a wiring diagram and start doing some testing.


On to the fogs not lighting:

As to the relay, the coil resistance sounds about right. 13.8 volts / 65 ohms = .212 amps. That's in the right ballpark for one of these relays. You are probably good there.

Have you run a jumper from the battery to the fogs to make sure they work? Have you tested for voltage getting to the fog housing when you turn on the switch? Check with a test light, not just a voltmeter.

RylandB96

I believe you got that right, although I'm also trying to diagnose.

Could you explain running jumpers to test the lights? (Couldn't find anything on that). Also, I assume the voltage should be around 12V when the switch is on, where would I place the leads?

Thanks for bearing with me! I do not have a test light right now
(I dig your name, I'll be moving to Western NC in August. Love them mountains)

Ajetski07

If the High Beams are engaged your Fog Lights will not come on. Also, your Fog Lights will not work when you do not have the head lights on at all. You must have your headlights on in the low beam position for your stock fog lights to turn on.

With this said if they are still not working when you are applying the switch in the correct way I cannot assist in diagnosing from there as mine always worked although sometimes would go off on one side. That was fixed when I installed after market Fogs and wired them into the stock harness.

BlueRidgeMark

That part is easy. Just disconnect the wires to the fog lights (bear in mind I don't have them, so don't know how they are connected) and run some wires to a good ground and to the battery + terminal. The idea is to make sure the lights aren't burned out. you don't want to spend a lot of time trying to troubleshoot relays and fuses and stuff when its a simple burned out bulb.

A lot of electrical troubleshooting is simply making basic function checks. Start with the most basic stuff so you don't spend time chasing ghosts.

Also, the more complicated it is, the more the need to write it down. Whatever you test, document it. It's really easy to forget what result you got when you did X vs. Y vs. Z. You can drive yourself in crazy circles.



Plugged into the meter, of course!


Juuusst kidding!


The black lead goes to a good ground, and do yourself a favor - get some good alligator clips and some rolls of wire to make longer leads. You can use them as jumpers or as extensions for your test leads. Having a black one and a red one in about 5 foot lengths (or even 10) can really make a huge difference. Especially if you don't have a helper.

The red lead goes to whatever you are trying to measure. And yes, about 12v. Check what you have at the battery. In theory, it should be 13.8 volts on a fully charged battery. Should be close to that.

You're going to like NC!

Ajetski07

Your fog light will have a lead wire that connects to the wire harness with plug-in connectors. You can unplug them under the bumper area, I am not sure how you will test them without cutting into them.

Ajetski07

Here are the plugs in this photo

RylandB96

Thanks for the suggestions and help everyone. Bulbs are not burnt out, brand new and tested on a battery. Ajetski07 and Mark, thanks for the info. I've unplugged those to check for corrosion and everything looked good. Guess I'll keep on testing!

BlueRidgeMark

Circuit splitting!

This is the preferred technique among electronics types. Lay out the circuit on paper. Understand what voltages should show up at what point, under what conditions. Identify the end point (in this case, at the bulb connectors) and the beginning point (the battery). Now identify some good test points in between.

Now, test at the end point. If that's good, pick one of those other test points that is near the middle of the circuit. "Middle" doesn't mean by actual distance, but functionally. That could be at a relay, or a switch, or something.

If you have the right measurements there, then you know the 2nd half of the circuit is okay. Find a test point halfway between your first test point and the beginning. Test that. Is it good? Move closer to the beginning. Is it bad? Move closer to the last known good point.

Get the idea?

And write down each step! You can drive yourself nuts otherwise!

BlueRidgeMark

Arrgghh! I said that backwards. If a test point in the middle shows correct results, you know the problem is AFTER that point, in the 2nd half of the circuit.

What a maroon!