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Fog lights ???????


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I want to replace my fog lights with spot lights. And, I want my fogs/spots to work while the bright headlights are turned on. As you know with the factory wiring the fog lights only work while the headlights are on dim. When you turn on the brights the fog lights turn off.

Is there a simple way to by-pass/override the switch that turns off tha fogs when you turn on tha brights???

Sure, I could hardwire tha fog/spot lights to tha switch but I thought there might be an easier way to override tha system. Like simply disconnecting (or splicing togather whichever is tha case) the wire/wires comming from the headlight brights switch)

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I'll see if I can hunt down tha wiring diagram...
Thanks but I already found one. Looks like I only have two choises.

 

Option #1 is to cut the power wire from the hi/low headlight switch going to the fog light switch and run power directly to tha fog light switch from any power source thats on when the ignition is turned on.

Option #2 is as above but run power to the fog light switch from the hot/on side of the headlight switch.

Naturally with #1 I could run tha fogs/spots without the headlights being on. With #2 I'll obviously have to have um on.

 

 

Unless yall can see another way to do it, I'm goin with option #2. I don't think I'll ever need my spot lights on without the headlights being on as well.

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Keep in mind that, by Federal and most state law, driving (spot) lights can be on ONLY when the high beams are on, and they MUST go off when you switch to low beams. However you choose to modify your wiring, be sure there is an interface to the high beams so the driving lights are on only with high beams.

 

And be sure you use a relay or you'll fry the switch in the dashboard very quickly.

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Keep in mind that, by Federal and most state law, driving (spot) lights can be on ONLY when the high beams are on, and they MUST go off when you switch to low beams. However you choose to modify your wiring, be sure there is an interface to the high beams so the driving lights are on only with high beams.

 

And be sure you use a relay or you'll fry the switch in the dashboard very quickly.

Awwww, your no fun at all. I figured I could charge people to pull um outa tha ditch when my lights blind um and they run off tha road. :rotf:

 

The factory wiring to the fogs already runs through a relay. All I'm doing is by-passing the headlight dimmer switch by supplying power directly to the fog light switch inwhich supplies power to tha relay for tha fogs. No the spots won't turn off along with the brights anymore but I don't intend to use um on the road anyway.

 

Ya know, now that I've come up with that light bar idea, I might just leave tha fog lights alone. :dunno:

 

Thanks for tha warnings.

Robert

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You will need a relay, There are usually wiring instructions on the package. But basically there will be 4 or 5 prongs on the relay.

one for the ground, one for power, one for a "trigger wire" and lastly one or two for the lite(s). You can put your switch in a couple places, on the ground works nice because you only need one wire running into the cab, BUT its a bigger wire. DON'T put it on the power wire as that too is a big wire. The trigger wire is another good place for the switch. You attach the trigger wire to what ever you want the new lights to come on with. IE the high beams.

 

CW

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If you have the stock wiring and relay for the fog lights you may try what the TJ's do by bending or using a piece of electrical tape to cover a pin on the relay. Here's a couple of links.

 

http://www.tmar.net/fog_lights.htm

 

http://www.getahelmet.com/jeeps/tech/fogrelay/

 

Not sure if the Renix era would be different as I haven't looked at the wiring for both to figure it out.

 

Piece of electrical tape should tell you pretty quick.

 

 

EDIT: Well, just looked at the wiring for the 97+ XJ's and it seems the pin they are bending is a trigger coming from the highbeam side of the light itself. After looking at the 88 MJ wiring, the relay is cut out of the picture by the dimmer switch all together so I doubt this mod will work with the Renix era wiring.

 

2nd EDIT: A diode between pins 1 and 3 on C177 should work, as it would allow power to the fogs when the high beams are selected by the dimmer switch.

 

:cheers:

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Look at it again and realized that the diode between pins 3 and 1 would still backfeed the low beams. :doh: It would actually take two diodes. One from pin 3 to the fog lamp wire coming from pin 1 and another from the fog lamp wire to pin 1 preventing the backfeed of power. Probably would be easier to just do the splice bypassing the dimmer switch all together.

 

:cheers:

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Probably would be easier to just do the splice bypassing the dimmer switch all together.

 

:cheers:

:agree: and by doing so the fog/spot lights would still be supplied power through the factory fog light relay.

 

Next question ........ is the factory fog light main power wiring to tha relay, tha relay itself and tha wiring thereafter to the lights capeable of handling twice as much wattage? (110 watts verses 200 watts) or (9.1 amps verses 16.6 amps) :huh???:

 

Damn thats confusing. :???: Lets git down to basics. ...... Could I burn up any of the factory wiring by nearly doubling the amount of power pulled by the higher watt bulbs?

 

How bout this ....... Has anybody replaced their stock 55 watt fog light bulbs with higher 100 watt bulbs and had any problems with the wiring burning up?

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Y'all making this much to complicated. :D Since I did not have factory fog/driving/and/or spot lights, I did not have the factory fog light harness after the left front bulkhead connector. But I did have the fog light switch already wired up in the dash (as all MJs do) to the bulkhead connector. I rewired the trigger signal to the existing fog light switch using inputs (12V and ground) from the existing cigar lighter circuit directly below the fog light connector in the dash. Then I used the existing fog light switch harness output for the relay trigger signal to the bulkhead connector pin 10 so I did not have to pull yet another wire thru the firewall. At bulkhead connector pin 10 I added my own relay and wiring out to the fogs. This bypasses the HI beam shutdown of the fogs and allows me to turn them on or off w/o a relay kill signal from the headlamp HI beam circuit. If you want the wiring diagram shoot me a PM and I'll send it. It's pretty easy and you don't have to mess with diodes. I'm using 100W fogs, and you can size out your relay and wire AWG gauge accordingly to handle whatever wattage lamps you want to run. :cheers:

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Y'all making this much to complicated. :D Since I did not have factory fog/driving/and/or spot lights, I did not have the factory fog light harness after the left front bulkhead connector. But I did have the fog light switch already wired up in the dash (as all MJs do) to the bulkhead connector. I rewired the trigger signal to the existing fog light switch using inputs (12V and ground) from the existing cigar lighter circuit directly below the fog light connector in the dash. Then I used the existing fog light switch harness output for the relay trigger signal to the bulkhead connector pin 10 so I did not have to pull yet another wire thru the firewall. At bulkhead connector pin 10 I added my own relay and wiring out to the fogs. This bypasses the HI beam shutdown of the fogs and allows me to turn them on or off w/o a relay kill signal from the headlamp HI beam circuit. If you want the wiring diagram shoot me a PM and I'll send it. It's pretty easy and you don't have to mess with diodes. I'm using 100W fogs, and you can size out your relay and wire AWG gauge accordingly to handle whatever wattage lamps you want to run. :cheers:
Naaa, I've got this. :thumbsup: Thanks for offering tha diagram though. :bowdown:

I'll let ya know if I let tha smoke outa my wiring harness. :roll:

 

I aint sceerd!!!

 

Thanks everybody.

Robert

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How is splicing one wire complicated? :D So what gauge wire and size relay did you use on those 100w lamps?

 

The factory wiring coming out of the relay is 14 gauge on the hot side to the lamps and 16/18 on the neg side. According to the table on the link below, it should be ok for the increase. However, if you think you need to increase to be on the safe side, you only should have to increase the output side of the relay which is located right behind the header panel.

 

http://www.rbeelectronics.com/wtable.htm

 

Watch for smoke.............

 

I was always tought if you let the magic smoke out of electronics, they won't work right afterwards.

 

:cheers:

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How is splicing one wire complicated? :D So what gauge wire and size relay did you use on those 100w lamps?

 

The factory wiring coming out of the relay is 14 gauge on the hot side to the lamps and 16/18 on the neg side. According to the table on the link below, it should be ok for the increase. However, if you think you need to increase to be on the safe side, you only should have to increase the output side of the relay which is located right behind the header panel.

I was always tought if you let the magic smoke out of electronics, they won't work right afterwards. :cheers:

 

My situation was different. I didn't have the factory harness, so I had to improvise. The fog light switch 3-pin connector was up under the dash with the output 12V trigger output going out on 18 AWG wire to the dead end forward bulkhead connector. So I supplied my own 12V input to the NO switch connector, grounded the indicator connector, and used the output of the switch to the harness that was already there. Picked up this trigger at pin 10 of the bulkhead connector and used that to trigger the coil side of a 40A relay I added. For the load contacts of the relay I ran 10AWG wire (overkill, but I had a bunch of it) fed w. a 30A fuse from the aux fuse panel I already had in place for my fans and H4 headlamps to the fog lamps. The original HI beam kill to the coil side circuit I discoed at the dash switch. Whew - been a long time ago and you guys woke up a bunch of dead brain cells. :cheers:

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Whew - been a long time ago and you guys woke up a bunch of dead brain cells. :cheers:

 

:rotfl2: I think thats what was happening when I edited my first post 2 times. I went to dinner and then woke up a few more to realize I was still screwed up. I forgot you have an HO era MJ. I was wondering if the relay mod I posted would work on the HO setup. I don't have any wiring diagrams from those to bounce it off of but you did mention the HI beam kill signal. I know with your setup it won't but someone with the stock setup may be able to take advantage of it.

 

:cheers:

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I was always tought if you let the magic smoke out of electronics, they won't work right afterwards.

 

:cheers:

Thats a fact!!! I don't know how they git that smoke in there but you damn sure know you've screwed something up when ya let it out. :doh:

I reckon they must put that unmistakable smell in too. :rotf:

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I did not have the factory fog light harness after the left front bulkhead connector. But I did have the fog light switch already wired up in the dash (as all MJs do) to the bulkhead connector.

Not so fast, Mate.

 

I currently have here an 86, an 87, two 88s and an 89. None of them have a factory foglight switch. The red '88 now has the switch, because I took the panel out of an XJ in a junkyard and installed it in the MJ, but I use it to control an aftermarket dome light.

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Kids.. :shake: All this sounds like a mountain of headaches... ;) ;) Why not just wire new stuff with a switch in the cab, (Maybe even use a factory switch) along with a relay on the firewall and your own wires as I mentioned earlier? Get some plastic wire loom and it will even look stock!! There are many trick options, you could loose the switch entirely and wire the trigger wire to the hi-beam factory wire and the lites will only go on with the high beams by them selves!!! Send the ground wire into the cab for a switch and not need to look for power source in there. Run the trigger wire into the cab, then out to the hi-beam factory wire and be able to switch on the lites, but only have them work with hi-beams.

 

PEACE OF MIND, No worries about IF you have the factory wiring, IF its going to be adequate, IF you have it wired right. Or even IF 20 something year old wires will even still work!! :yes: :clapping: :brows:

 

I have probably wired in 20-30 sets of lights for my self and for friends just like I am describing. Once you get your head around how it works, its very straight forward, not very expensive and very reliable. WAY better then factory as you can tailor the wire size to your electrical requirements. If in doubt, just go up a size or two in wire. Remember DC electric is like a water pipe, bigger means more flow, more flow is LESS heat. Heat in electric is resistance and that's what kills.

 

CW

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Kids.. :shake: All this sounds like a mountain of headaches... ;) ;) Why not just wire new stuff with a switch in the cab, (Maybe even use a factory switch) along with a relay on the firewall and your own wires as I mentioned earlier? Get some plastic wire loom and it will even look stock!! There are many trick options, you could loose the switch entirely and wire the trigger wire to the hi-beam factory wire and the lites will only go on with the high beams by them selves!!! Send the ground wire into the cab for a switch and not need to look for power source in there. Run the trigger wire into the cab, then out to the hi-beam factory wire and be able to switch on the lites, but only have them work with hi-beams.

 

PEACE OF MIND, No worries about IF you have the factory wiring, IF its going to be adequate, IF you have it wired right. Or even IF 20 something year old wires will even still work!! :yes: :clapping: :brows:

 

I have probably wired in 20-30 sets of lights for my self and for friends just like I am describing. Once you get your head around how it works, its very straight forward, not very expensive and very reliable. WAY better then factory as you can tailor the wire size to your electrical requirements. If in doubt, just go up a size or two in wire. Remember DC electric is like a water pipe, bigger means more flow, more flow is LESS heat. Heat in electric is resistance and that's what kills.

 

CW

I agree completely. Driving (spot) lights are much easier than fog lights. Just do it as CW proposes.

 

You can do the same with fog lights, using a tap off the low beams for the trigger, but then you don't have the option of running fogs with just parking lights. That's why doing a "proper" setup for fogs gets a bit more complicated.

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Kids.. :shake: All this sounds like a mountain of headaches... ;) ;) Why not just wire new stuff with a switch in the cab, (Maybe even use a factory switch) along with a relay on the firewall and your own wires as I mentioned earlier? Get some plastic wire loom and it will even look stock!! There are many trick options, you could loose the switch entirely and wire the trigger wire to the hi-beam factory wire and the lites will only go on with the high beams by them selves!!! Send the ground wire into the cab for a switch and not need to look for power source in there. Run the trigger wire into the cab, then out to the hi-beam factory wire and be able to switch on the lites, but only have them work with hi-beams.

 

PEACE OF MIND, No worries about IF you have the factory wiring, IF its going to be adequate, IF you have it wired right. Or even IF 20 something year old wires will even still work!! :yes: :clapping: :brows:

 

I have probably wired in 20-30 sets of lights for my self and for friends just like I am describing. Once you get your head around how it works, its very straight forward, not very expensive and very reliable. WAY better then factory as you can tailor the wire size to your electrical requirements. If in doubt, just go up a size or two in wire. Remember DC electric is like a water pipe, bigger means more flow, more flow is LESS heat. Heat in electric is resistance and that's what kills. CW

 

Exacerly. I just used the existing stock harness wire to transport the ground trigger signal from the dash switch to the forward bulkhead connector - no amperage there. Then added my own properly sized relay and wiring harness out to the fog lights.

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OK, so what your saying is if you connect your thingamajig to tha doohickey, your whatchamacallit oughta work but only of your deallyflopper doesn't interfere with your dodad. RIGHT??? :thumbs up:

 

EXACTLY!! :ack: BUT that's only on days ending in "Y" and as long as the mass of the @$$ remains constant. :rotf: :rotf: :ack:

 

Like I said in the first post, wiring explanations are on most relay packages. There are 4 or 5 posts on a 30 or 40 amp relay.

 

#30 is for fused power into the relay.

#85 is for the relays ground.

#86 is the trigger wire, run a small like 18/20Ga wire here as no big power/amperage is needed. This wire only "fires" the relay itself.

#87 (&87A) go out to the item you need to power. The "A" works nice if your wiring lights as you use one wire for each lite.

 

CW

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Piece of cake. :thumbsup:

 

I've never had a problem wiring anything from scratch. Been there, done that countless times. I just needed a few pointers on tha factory wiring for tha fog lights and how to keep tha dimmer switch from turning um off when you go to high beams. Now that I know how tha system works, I won't have a problem making it do what I want it to.

 

 

Thanks for tha help everybody.

Robert

 

BTW ..... I'll use this when I run my light bar lights. Thanks!!!

 

#30 is for fused power into the relay.

#85 is for the relays ground.

#86 is the trigger wire, run a small like 18/20Ga wire here as no big power/amperage is needed. This wire only "fires" the relay itself.

#87 (&87A) go out to the item you need to power. The "A" works nice if your wiring lights as you use one wire for each lite.

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