My first post. I've been a
member and forum lurker for almost 2 years now though. Before continuing, I just wanted to say thanks to everyone on this forum - it's been a fantastic resource.
I'm long-winded and I know it. So my apologies in advance. I like to be meticulous and detailed so I don't generate more confusion and questions instead of clarifying an issue.
Ok, to business...
Have a 2000 Limited. Just bought a 97 Sport. The Limited, of course, came with factory fogs, so nothing to do there. But I want to use a factory fog switch - and wiring if possible - to control the fogs that the previous owner installed on the 97 Sport. I have already bought the switch and bezel for a 97. So at this point, I just need to figure out the wiring.
The fog light dongle (connector) is already in the dash wiring harness in the 97 Sport. It is identical to the wiring harness in the 00 Limited. I was hoping it would be as easy as plugging in the switch, but no such luck. The wiring harnesses in each vehicle performs almost identically, with one small (yet show-stopping) difference.
In the 00 Limited, the wire harness works like this:
- Black: Ground
- Purple: Input, indicates the state of the high beams
- 0V when lights are off
- +12V when running or low beams are on and high beams are off
- Back to 0V when high beams are on
- Blue: Output, controls power to the fog lights
- 0V when running lights/low beams are off and/or fog light switch is turned off
- +12V when running lights or low beams are on and fog light switch is on
- 0V when high beams are on, regardless of fog light switch turned on or off
- Orange: Input, indicates state of running lights/low beams
- 0V when running lights/low beams are off
- +12V when running lights/low beams are on
- +12V when high beams are on
So, essentially, the orange wire acts as a trigger to show the lights are on, allowing the fog lights to be turned on using the switch. The purple wire acts as a high beam trigger. As long as it has current, the high beams are off, so the fog lights will work. But if you turn the high beams on, it kills the current in the purple wire, and subsequently kills the fog lights. So you must have +12V in both the purple and orange wire to be able to send +12V to the blue wire using the fog light switch.
So here's the problem: in the 97 Sport wiring harness, the purple wire
never gets power. So regardless of the state of the high beams, there is never any current flowing in the purple wire. Because of that, the fog light switch "thinks" that the high beams are always on and will never send current to the blue wire.
I took the 2 relays out of the power distribution center (PDC) under the hood on the 00 Limited and put them in the same positions on the 97 Sport. They're labeled differently on their respective PDC covers and owner manuals, but they're both still for fog lights. I tried putting in one, then the other, and then and both; still no current in the purple wire. I also checked all of the fuses in both the PDC and the fuse box in the cabin (behind the passenger kick panel). Both Jeeps have identical configurations, and all fuses are present and working. I did notice that one of the relays in the PDC didn't feel like it was actually plugging into anything. It almost seemed to just drop into position, without any friction resistance. I'm wondering if perhaps there are some connections inside the PDC that are missing so that relay isn't really doing anything.
One very easy solution to this would be to remove the purple wire from the connector, splice a wire onto the orange wire, and reconnect it into the connector. That would send +12V to the switch for the purple wire position, tricking the switch into thinking the high beams were off. As an added benefit (or drawback perhaps), the fog lights would stay on regardless of whether or not the high beams are on.
I'd like to avoid doing that if possible for 2 reasons. First, I'd like to avoid encounters with the fuzz. Second, I plan on using another relay in the future to use my fog light switch to control some lights on the roof whenever the high beams are on. So the same switch wold turn on fog lights when the running lights/low beams are on, and roof lights when the high beams are on. Good for night-time wheeling and for sending a subtle message to those pesky drivers who refuse to dim their high beams.
So what am I missing? How do I get that purple wire to behave itself and play nicely with others?
Thanks in advance for your inputs. And again, sorry for the short novel.
