I have been trying to decipher the fog lamp wiring diagram for my '93 Grand Cherokee Limited. It looks like there is a relay in the circuit, but on the Front End Lighting page where they show the lamps, It shows (With Baja Group.) I have looked through all the brochures I have on the '93 GC and I don't see any Baja Group as an option. Maybe it was one of those dealer installed things.
I have two questions. Do all '93 Grand Cherokee Limiteds use a relay for the factory fog lamps, and does anyone know how much current the relay can handle? I am assuming it was probably designed for two,
55-watt lamps. The Baja Group thing leads me to believe it might even handle 100-watt lamps.
The relay is in the relay center behind the battery.
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Fogs are a dealer installed option (or could be) Basically it was a replacement switch inside, a relay, and a harness that extended the existing wiring harness (just behind the grill) to the new fog lamps. (plus some ugly cutting of the front bumper)
I built my own with projector fogs (55W) using the same harness and a custom switch fit into the center console.
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(crappy page)You can just see the switch at the top of this picture.http://revbeergoggles.com/fire-extinguisher.jpgIt has a built-in 12V led light (radio shack part). I wired thelight to be on with the fogs and dimmed with the dash lights. Somewhere I have a schematic.. That was pre webby days. :) I'll keep looking.
As for how much current, that depends on the wire gauge and length. It was made for 2 55W lamps but is not properly sized for 2x100w and will burn the wires. The existing wire is just 20ga, just enough (barely enough) for the factory fogs.
To run two 100W lamps you would put in two more relays. Each for 100W and key those off the existing relay.
Little wire cheat sheet. Always go with a smaller gauge (larger wire) if your close to the number... so for 3-5ft you would be fine with 16 Also if you do this remember to properly fuse the supply. 15-20A depending on startup current. Fuse goes as close to the battery as possible.
Thanks Doug and Bill. Today at the carwash, they cleverly broke one of the lenses on a factory fog lamp. On the '93, they sit on top of the bumper. This is the second lamp broken by a carwash. I went to the Jeep dealer, and they wanted $139.45 for ONE lamp. They don't sell just the lens for that model. Anyway, the carwash dealer said he would pay for a new one. When I saw the price, I went to an auto parts store and bought a pair of Hella driving lamps for half the cost of the single Jeep replacement lamp. I figured the carwash mgr would really balk at the $139.45. He probably thought $30 or so, although I imagine I am not the first he has had to replace. The Hella's are much nicer lamps than the factory units, so I am happy with the outcome. They are 55-watt, so even though they come with a relay, I assume I can just replace them using the stock Jeep wiring that includes its own relay.
A new Sony radio for the JGC came today too. Looks like this weekend won't lack for things to do. :-)
Keep in mind the way the ZJ fogs work is power is applied to the relay only when the low beams are on. That's for legal reasons.
I found the schematic but not my notes.
Tapped L35(20 Brown/Red) and switched to ground to turn on the fogs (still locked to low beam only)
To light the LED I pulled off L416(Violet/Orange) from the shift light, fed it through a resistor, a diode (to limit current direction) and then through the LED. If the LED is not rated for 12V you need a current limiting resistor. Choose one larger than suggested since you don't want a blinding light.
Yep.. 139 for a real piece of crap fog lamp is about right. ;] That (and the cutting of the bumper) was behind the decision to do my own.
But if you want $$$$ look at the rear plastic lamps. I caught one starting to seperate and fixed it with epoxy before water could get in and corrode the reflecty material.
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