Fog Lights Relay Box

[Obscure]

Good morning everyone, reading in the forum I found the location of the fog light fuse box (under the air filter).
I found the location of the fog light relay, which I will replace to try to make them work.
I would like to know if it is correct that the "fog lamp isolation relay" is missing and what purpose it serves.
When in doubt, I bought two.
Thanks for your help

 

[J_C]

I can't definitely answer your question. The isolation relay does not show up on a wiring diagram I have, but I have read that others claimed its purpose is to shut off the fog lights when the high beams are used.

I would just try it without that relay, or if you are ambitious, I suppose you could pull the relay box and see if there is wiring to the isolation relay position, but I wouldn't bother doing that unless everything else checks out yet the fog lights still don't work. I don't like to disturb quarter-century old wiring if I don't have to.

 

[Obscure]

Thanks for the advice, I'll keep it and update you.

 

[410Fortune]

Some good info

Wiring Foglamp Relay to Work with Hi Beams - 99 Ranger - Ford Truck Enthusiasts Forums

1983 - 2012 Ranger & B-Series - Wiring Foglamp Relay to Work with Hi Beams - 99 Ranger - The goal is to wire the fog lamp relay so that they do not turn off when the high beam are activated. There are two very good threads (links below) that I have been studying that describe the steps to do...

www.ford-trucks.com

 

[Obscure]

Update:
The relay in question works.
I discovered later, that the front fog lights only come on when I activate the high beams.
I confirm that fog light isolation relay is not wired.
I keep them as they are
Thank you Guys

 

[J_C]

^ Seems a little backwards, to have them only come on with high beams.

Normally if there is fog, the further/higher throwing high beams will more easily blind you with a wall of illuminated fog. Then again they didn't really care all that much or else the fog lights would have started out a more amber color.

 

[Obscure]

I agree.
I will look for some amber LED lights, to be mounted inside the bumper grille, under the license plate.

 

[410Fortune]

The factory wiring has fog lights only come on with parking lamps or low beams

Activating the high beams shuts the fog lights off, in the factory configuration

 

[Queensboy]

The factory wiring has fog lights only come on with parking lamps or low beams

Activating the high beams shuts the fog lights off, in the factory configuration

Could he have the wrong relay or wired incorrectly? N/O vs. N/C?

 

[J_C]

Could he have the wrong relay or wired incorrectly? N/O vs. N/C?

I hate to speculate because a vehicle this age, (that has had more than one owner ?), could have been modified over time.

However the feed to the fog lights relay is always live, so if he had gotten hold of some unusual relay for this form factor that is normally closed instead of normally open, that would result in the fog lights always being on until the relay is triggered, even with the vehicle and everything else shut off. I think we can rule that out, unless the way to turn them off is to press IN the dash fog lamp button, the opposite of the normal dash button function, and then that would mean constant current through the relay coil with vehicle off, would show up as additional parasitic current draw above the typical ~25mA once the vehicle is timed out from the battery saver circuit and asleep in its (otherwise) lowest current drain state.

Easiest would be just look at the part # for the relay but I doubt that it's normally closed, especially since the vehicle does not seem to have the fog light isolation relay used, so "probably" is the same circuit I saw in the wiring diagram.

If it is the same circuit, the only thing that comes to mind that makes sense is that someone has rewired the high and low beam circuit such that the relay coil is grounding through the high beam bulb element instead of low beam. Unplugging the headlamp connector (right headlamp) and checking resistance between its high beam and fog lamp relay socket pin 1 would verify this, since it should instead have low resistance between only the low beam contact and relay socket pin 1. Wiring diagram I'm looking at is attached.

 

[410Fortune]

Any chance new headlight bulbs were installed recently? I know from experience that when led bulbs are clocked upside down in the housing the low beams will look like highs and the highs look like lows
Just something to think about

 

[Obscure]

All lights are installed correctly, the european version has H4 as low beam and high beam. They can only be mounted in one direction because the teeth of the lamp holder must match.
In the past the old owner certainly modified the functioning of the fog light system.