Tuning Aftermarket Foglamps on With Your Headlights

[Falcon]

I think you nailed it with the blown bulb data. On one hand, I agree that it is more complex than it needs to be... but good data is good data... it just depends on what you do with it.

I am still wanting one of our Ford Master Mechanics to weigh in on this... I didn't touch on some aspects of possible situations due to the desire to make it simple... but there are issues if it is truly a PCM system. And the more I think about it... it HAS to be.

Falcon

 

[frogslinger]

The other piece of evidence that tends to make me think that it might be is what happened to Dan's truck with the break lights jacking up Hill decent... not conclusive but...

 

[Falcon]

Hmmm... excellent point. If it was water from the sat ant - it could have been sending a steady ground to the bus (or worse an intermittent one). At that point... just flip a coin as to what else will be affected. What else goes thru that trunk at that time? Hill descent data? Or, since it is a brake lite, and ABS is an integral part of the hill descent... Hmmmm.

Falcon

 

[MarkT]

If you look at the diagram FSM posted, you'll see that he has tapped into the circuit after the high beam headlight relay.

If there is any computer controlled PCM chicanery going on in the head lamp circuitry, it is well before the high beam relay...

(Which is why you would not want to tap into the circuit under the dash someplace... you could mess something up if you did that)

 

[frogslinger]

If you look at the diagram FSM posted, you'll see that he has tapped into the circuit after the high beam headlight relay.

If there is any computer controlled PCM chicanery going on in the head lamp circuitry, it is well before the high beam relay...

(Which is why you would not want to tap into the circuit under the dash someplace... you could mess something up if you did that)

Good answer... I had assumed that initially when I was thinking about doing this, but the post on the Z made me leery...

 

[Falcon]

If you look at the diagram FSM posted, you'll see that he has tapped into the circuit after the high beam headlight relay.

If there is any computer controlled PCM chicanery going on in the head lamp circuitry, it is well before the high beam relay...

(Which is why you would not want to tap into the circuit under the dash someplace... you could mess something up if you did that)

Precisely Mark... which is why I am raising the question of PCM logic in the truck. The SJB (Smart Junction Box) nomenclature smacks of bus end point. If there is a state feedback loop for the high beams it would be in the SJB, I believe. It's all doable... just need to know the facts.

Falcon

 

[FSM06]

In all of the research I did trying to figure this one out, I made several mach lighting set-ups just using jumper wires and temp connections. As long as I was on the ouptput side of the relay, the SJB did not care what I did. The initial set up I tried was tying a relay into the low beam circuit, but since it was a micro-transistor controlled circuit, the SJB sensed the excess load of the relay's primary windings and would not operate both the low beams and the relay. The SJB has logic that can sense or detect high resistance, an open circuit, shorted to power circuit, etc. The park lamp circuit is also controlled by a relay as the high beams are so the other set up we discussed previously with the four pin relay will work as well.

FSM

 

[Falcon]

I SEE... said the blind man... as he picked up his hammer and saw. <G>

thanks!

Falcon

 

[OBXRAPTOR]

First and foremost- a gigantic THANK YOU to FSM06 for putting this together for the electrically challenged. Please forgive me if this is a stupid question, but:

In the first circuit diagram are 87 and 87A labelled in reverse compared to the PIN connector diagram you wrote- does this make a difference?

thank you

 

[FSM06]

First and foremost- a gigantic THANK YOU to FSM06 for putting this together for the electrically challenged. Please forgive me if this is a stupid question, but:

In the first circuit diagram are 87 and 87A labelled in reverse compared to the PIN connector diagram you wrote- does this make a difference?

thank you

OBX, you are correct, the "shop towel" drawing is incorrect. The leg from the fog lamps should be on 87a, not 87. Must have had a small brain fart when I drew that one! Sorry about that all, and thank you for the question OBX. I will try to get a new drawing corrected and posted in its place.

FSM