Foglights failed to work for a short while...

[CTScott]

I would definitely suspect the switch. Some of the aftermarket fog kits use really poor quality switches.

[EPyarisdriver]

This save me today from another sleepless night. Switched the fuses and now on and work perfect!!! YES!

[Ratz]

I just prepared little troubleshooting guide for fog lamps. I hope someone will get some use from it.



Top horizontal slot goes to fog lamps. If you apply 12 Volt current to this slot fog lamps should illuminate. If not, the bulbs are burned out or there is open in the wiring to the lamps. If you take VOM and check the resistance from the top horizontal slot and your positive pin plugged to the bulb (removed for testing purpose) and you find continuity, then your positive wire is OK and you need to check the ground wire from bulb plug to ground on vehicle body or frame.
If you have only a test light connect the clip to the battery positive terminal and touch this slot with tip of the test light. the light should be lit.

Second horizontal slot from the top is a power supply to the fog lamps. This terminal should be alive (positive 12 Volts) all the time. If not it is likely fuse problem, but could be that wire got loose from power supply. If you have only a test light, connect the clip of the light anywhere on the body (not painted or rusted surface) and with the tip touch this slot. Light should be on. If not change the fuse.

If you place a jumper between the two top horizontal slots the fog lamps will come on with some arcing as the draw will be about 6 to 8 Amperes for stock lamps.

Left vertical bar goes to fog lamp switch. Please note that the switching is done by ground. If you have only a test light, connect the clip of the light to the battery positive terminal and touch this slot with the tip of the test light. While turning the fog lamp switch on the light should come on. If not it is likely the switch.

The right vertical slot must have power for relay to operate. This one is little tricky as it depends how the fog lamps were wired in. # 1 is the OEM way. 1) Fog lamps turn on only with the low beams. 2) Fog lamps turn on with the parking lights, low beams or high beams. 3) Fog lamps turn on anytime. If you have only a test light, connect the clip of the light anywhere on the body (not painted or rusted surface) and with the tip touch this slot. The light should light up. If not, turn headlamps low beam. If test light still does not come on it is likely the headlamp switch.

If all tests pass, it is likely the relay.

[EPyarisdriver]

What if everything works you just dont hear the little tick you usually hear when the lights turn on. Is it still the relay? Im running a bigger fuse so would I need a better relay?

[Ratz]

"What if everything works you just don't hear the little tick you usually hear when the lights turn on. Is it still the relay? I am running a bigger fuse so would I need a better relay?"

Explain what you mean by “What if everything works”. Do you mean all the tests are satisfactory according to my post? Or your lights work fine and you do not hear a click of the relay?
By running bigger (I assume larger Amperage) fuse, you do not need a bigger relay. Larger fuse then specified by the manufacturer could have negative effect on your wiring in case of short or higher light draw as wiring could become overheated and melt in process.

You can test the relay by mirroring the four terminals on the relay when you remove it. Take it to the battery and touch the positive side of relay to positive battery post. Than take a piece of any wire and touch the terminal I referred to in the picture as “Ground controlled by fog lamp switch” to battery negative terminal and you should hear the relay click. If it does not it is likely a failed relay. There is few of them on eBay. Our cost in Canada is about $120. Part numbers are 9098702020 for the 2011 and 9098702022 or 9098702027 for earlier models.

[EPyarisdriver]

All the tests passed but now Im gonna try checking the relay with the battery and see if I can hear it.
And what I meant is the lights do NOT work.
Sorry for the confusion

[Ratz]

Originally Posted by EPyarisdriver

All the tests passed but now Im gonna try checking the relay with the battery and see if I can hear it.
And what I meant is the lights do NOT work.
Sorry for the confusion

Further to what I wrote:

You can test the relay by mirroring the four terminals on the relay when you remove it. Take it to the battery and touch the positive side of relay to positive battery post. Than take a piece of any wire and touch the terminal I referred to in the picture as “Ground controlled by fog lamp switch” to battery negative terminal and you should hear the relay click. If it does not it is likely a failed relay.

Some relays can be really quiet (unusual) so while you are applying power to the above stated terminals and listening for the click, in addition you can connect a ohmmeter to the two remaining terminal. Set the ohmmeter to 200 Ohms scale and watch the gauge while you are connecting relay to the battery. You should see a deflection in the ohmmeter display. If you want to practice what you should be seeing in the ohmmeter display, just with the same setting touch the leads of the ohmmeter together and watch the screen. It should change providing your meter is turned on and battery in the meter is good.

If you used VOM before I apologize for the detailed description.