I recently installed the factory fog lights in my 1998 f150. The plug ins were already there and the light switch also.The problem I am haveing is they do not switch on. I can not locate the fog light relay, all the info I have found tells me it is in the underhood fuse box, yet the legend does not list such a relay. does anyone know where this relay is?

 

It should be in the fuse box on the L. on the inside fender well. If the legend doesn't show a relay for the FL, if you have an extra relay, you could try plugging it in one by one to the relay cavities that aren't being used to see if one of them is it. Keep in mind that there is probably also a fuse that may have to be installed in addition to the relay for them to work. The relay box may also be an auxiliary box on the side of the underhood fuse box.

 

The 97 & 98 MY have the relay panel external to the BJB ( aka Battery Junction Box, engine compartment fuse panel ), that is not documented in the owners manual for some reason ( the 98 OM also does not include the engine mini fuse panel ).

I am going to take a SWAG, that the fog lamp relay is the one marked unknown in this picture or the slot next to it, if that is not it.

 

thanks 4 the info. it helped somewhat. i ended up going to alldata and the relay was where your picture showed. the problem was that the original switch was missing the terminal to ground the relay and turn on the lights. a new switch solved the problem.

 

I'm having this same issue. I have the external relay panel that is shown, but there is no relay in the 'unknown' location. I purchased the relay from O'Reilly, and there aren't even any wires going to this location. My fog lights are factory installed, and worked just fine until about 6 months ago. Replaced both bulbs and fuse.

 

Did you check to see if there was + VDC at the bulb connector before changing bulbs ?

What fuse did you change ?

Are there any modifications to the truck ?
- Any not just if you think it is related.

 

The fog light relay is in the fuse box under the hood, not in the add-on box next to it. See the owner's manual.

 

SScully, no I did not check for +12 vdc at the bulb connector. The fuse I changed was a 5 amp in the passenger compartment fuse block marked #27 as identified in my owner's manual. The truck is pure stock, 250,000 miles.

projectSHO89, my owner's manual does not identify one of the six relays in the power distribution box (see picture above) as being the fog light relay. Even so, I tried swapping out each of those with the new one I purchased. No luck.

I think I'm down to tracing the wires from the fog lights on back, looking for broken/chewed wires, etc.

 

That is the fuse for the switch to the coil on the fog lamp relay, not the fog lamps themselves.

The fuse for the fog lamps is Power Distribution fuse # 9, 15A

 

Well, dug a bit deeper and it seems that the schematics upon which i based my previous comments on are incorrect as to the location of the Fog Lamp Relay.

Here's the good news: I found a diagram in the WSM that shows the location of the FLR and it seems that Mr SSculley's SWAG is correct, it is the one marked as UNKNOWN in the photo of my old 97's add-on relay box. That truck, now gone almost four years, didn't even have fog lights.

ps89

 

Hello,

I installed fogs on my canada made F150. It had the wires down front. I got a switch. used off the auction site. I got the light housings there too. 9006 bulbs and the connectors like I mentioned were under the car. Plugged it all in and no foglights come on, either side. The bulbs are good.

So, I can't figure what might be wrong. I checked the 27 fuse inside and the 9 fuse under the hood. They are ok. I also checked the relay by swapping it with another, though your picture above is the only one to identify the relay that I can find on the internet. It is the bottom left one in the photo in the 2ndary relay box on my truck, I hope. I did a swap check to verify that is not the problem.

I am turning the truck on to check it.

So I have some photos that maybe somebody can comment on. 1st, my truck has no black/white wire going to the 3 pin connector with one pin shown on the internet in places about this. I just have the 2 multiwire connectors. I looked inside the dash and cannot find a 3rd connector to go to the light switch. Do I need this to make the fog lights work? The schematic I saw showed this 3rd connector with a white wire, black strip as critical for the fog light circuit. Is this wire likely hidden somewhere in the dash? Anyone ever found it and know the location?

Any help on this would be great! I did a voltage check on the underhood 15a fuse and it is hot both sides so I have the power but I have no easy way to see if/how the relay is being activated. The pin numbers I have on the schematic and the little schematic diagram don't match up so I am hesitant to start shorting things out.


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Yes the white w/ black stripe wire is critical to making the fog lamps operate. It is what powers the coil on the fog lamp relay.

If it is not in the connector, chances are it was not added to the truck when manufactured. This is normally the problem with members trying to add fogs lamps to a non fog lamp truck.

The easiest route is to get a connector ( or just the pin & wire ) from the junk yard, and add it to the switch. Use this to power a standard aux lamp relay under the hood ( instead of the switch that comes with the kit ).

The only other option is to get the connector & wire and the relay socket pin & wire to add this to the fuse panel.

It will be much easier to use an aux lamp relay kit, that way all the work is at the switch side and to under the hood.


1997 EVTM 86-1 Fog Lamps

 

Wow, thanks for getting back to me on this SCCULLY! The fog light wires were down near the fog lights I put on. I plugged them in. These wires must go somewhere on the opposite end.... Do they go to the fog light relay? Should I run new wires to the fog lights separate from the ones that were there?

Were you suggesting giving up on any of the stock wiring and just putting in a new relay, new wires to the fogs? I am probably just slow getting it.

I am posting a pic somebody else posted of the fuse box and aux relay box. Is the red circled relay the fog light relay? The empty (no wires) relay spot is next to it with the blue arrow.

If I use the red circled relay, and the power from it is going down to the fog lights, do you know which pin the white and black wire goes to? I cannot see a pin number on the slots where the relay plugs in. I pulled the relay and on 'relay pin 4 slot' there is no connector in the slot. Is that where the white/black wire goes? I may be able to get a pin for that slot and run it into the car. I am pretty good with all that, field engineer for many years.

I think you may be one of the few folks that knows the details on this! I could not find any reposted ford info, for sure.


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SScully, looking at your drawing again, it appears to have the correct pin numbers for the relay I have, matching the side diagram on the relay.

However, there is a female socket at relay pin 1. I am guessing Ford installed the black/white wire from the pin 1 to the firewall passthrough junction which is likely the C158M to C158F junction shown on your drawing too. That'd mean they did not run the W/BK (white/black wire) from C158F inside the truck to the switch. Or, the b/w wire is hidden up in the dash so it is hard to find.

Let me know if you agree on this. If so, I just need to connect on to the white/black wire in the engine compartment, get it through the firewall, then connect it to the remaining connector/pin on the switch. Thats actually easier than doing a new relay, and running a completely separate wire.

 

From a few MY ranges ( 97/98 01-03 and 04+ ) the wire from the fog lamp switch to the fuse panel is not there.
Where it is missing I have never seen someone ID, continuity checks show an open.

It is strange, as you found out ( and others ) the fog lamp connectors are installed all the way to the fuse panel.
If you have the 15A fuse in the underhood fuse panel, and jumper the Normally open contacts, the fog lamps will illuminate.

I have seen this up to 2008 MY F150s.

It is up to you if you want to try to run the wire to the fuse panel or if you just want to go with an Aux lamp relay kit to power the factory mounted fog lamps.

You can purchase a kit or make one yourself, which ever you find easier.

This is a sample Aux lamp kit diagram


In you case, you would get the pin and wire from a headlamp switch from the junk yard, and use the factory switch in place of the switch in the diagram above.

Depending on the MY switch you got, you are either switching ground on the coil on the relay or power.

MY 2000 I do not recall which way it is, 97 to 99 is switching ground as the diagram above shows, MY 2001 to 2003 is switching power.



2001 EVTM 86-2 Fog Lamps

Depending on which MY switch will show how many pins you will need to get.
the MY 2001+ switch is easy as the White w/ black stripe wire is spliced to the brown wire for parking lamp power driving the fog lamps, no need to add in fuse #27.