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Disabling overhead display dimmer?

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City, State
Bonita Springs, FL
Year, Model & Trim Level
2000 XLT, V6 OHV
Hey everyone, I like to drive with the parking lights on during the day and unfortunately for me, that causes the temperature and compass display to dim. Is anyone here familiar with the wiring for the overhead display harness and what controls the temperature display dimmer? I just need to know which wire color to cut :D I don't mind it being bright at night either.

Thanks in advance.
 



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I'm not sure what wires control the display dimming, but that is an interesting problem.

I too like to have headlights on, all of the time, but be able to shut them off, and have it do that automatically. I'm interested in what this turns up, which wire(s) deal with the dash lights dimming. I would prefer to use two sensors to control the systems, one for the interior lights, and the oil pressure for the headlights. The trick should be to simply remove the light sensor control of the headlights, reroute that trigger wire from the oil pressure instead. When the engine starts, the lights come on. I have the automatic lights(mirror), so the lights still stay on with the delay control too.
 






I'm not sure what wires control the display dimming, but that is an interesting problem.

I too like to have headlights on, all of the time, but be able to shut them off, and have it do that automatically. I'm interested in what this turns up, which wire(s) deal with the dash lights dimming. I would prefer to use two sensors to control the systems, one for the interior lights, and the oil pressure for the headlights. The trick should be to simply remove the light sensor control of the headlights, reroute that trigger wire from the oil pressure instead. When the engine starts, the lights come on. I have the automatic lights(mirror), so the lights still stay on with the delay control too.

I found an old post that describes what the pins and wires do in the overhead display harness. If you scroll down you'll see that there's a pin that provides power to the compass display. Maybe if I cut it and wire it to another power source, it won't dim when the lights switch is on. That's the best I can think of at the moment.

http://www.explorerforum.com/forums/index.php?threads/interior-lighting-wiring-schematic.217008/
 






Good find, that's a great source, the thread shows some good wiring tricks and how to alter the display by switch and relay, different bulbs too. I would still like to change my green displays to blue, but that is a lot of work and some is easy, other items are really tough.

For your use though, just to be able to run the lights during the day, why not instead isolate the one headlight circuit from the rest of the lighting? Since you want to leave the rest of the lighting working as stock, I'd leave that part alone, and go to the wiring that turns on the head lights, and interrupt that. You can keep the normal interior lighting working as it is, and use an alternative method to turn on the headlights, or just the running lights, when you want them on(without affecting the interior etc). I'm saying don't use the dash headlight switch to turn on the external lights you want on, use another trigger for them, and a diode as needed to keep from back feeding the untouched lighting circuits.

I used the oil pressure dummy light circuit for my 99 truck, just one wire to trigger my headlights. But I didn't isolate that from the rest of the lighting, so I'm sure it means that my interior lights dim during the day when the headlights are on. That hadn't bothered me, but I guess I should take a look at that again and see if it needs some further modification. I went into the trigger wire from the light sensor on the dash, and cut it there and substituted the oil pressure sensor signal. It's been since 2006 that I did that, so I've forgotten where exactly that was. I made tons of wiring changes, so that one was minor and I don't recall many fine details.

Keep brain storming, it's cool to see what you and others think of.
 






Good find, that's a great source, the thread shows some good wiring tricks and how to alter the display by switch and relay, different bulbs too. I would still like to change my green displays to blue, but that is a lot of work and some is easy, other items are really tough.

For your use though, just to be able to run the lights during the day, why not instead isolate the one headlight circuit from the rest of the lighting? Since you want to leave the rest of the lighting working as stock, I'd leave that part alone, and go to the wiring that turns on the head lights, and interrupt that. You can keep the normal interior lighting working as it is, and use an alternative method to turn on the headlights, or just the running lights, when you want them on(without affecting the interior etc). I'm saying don't use the dash headlight switch to turn on the external lights you want on, use another trigger for them, and a diode as needed to keep from back feeding the untouched lighting circuits.

I used the oil pressure dummy light circuit for my 99 truck, just one wire to trigger my headlights. But I didn't isolate that from the rest of the lighting, so I'm sure it means that my interior lights dim during the day when the headlights are on. That hadn't bothered me, but I guess I should take a look at that again and see if it needs some further modification. I went into the trigger wire from the light sensor on the dash, and cut it there and substituted the oil pressure sensor signal. It's been since 2006 that I did that, so I've forgotten where exactly that was. I made tons of wiring changes, so that one was minor and I don't recall many fine details.

Keep brain storming, it's cool to see what you and others think of.

Yeah I'll definitely keep checking. I'm kinda sure than my solution will work, if not I can just solder the wire back together. I love modding the X. So far I've changed the interior lights to LEDs and I've added the back up sensor system using the stock harnesses already in the truck. Next up I'm adding heated mirrors, led turn signals on the side mirrors, a message center and hopefully the electronic climate control. Good luck with your mods too.
 






I would still like to change my green displays to blue, but that is a lot of work and some is easy, other items are really tough.

Since you have a '99 with the green backlighting you could use the parts from a '97 or earlier 2nd gen with the blue backlighting. All parts are a direct swap. Just a thought.
 






Yeah I'll definitely keep checking. I'm kinda sure than my solution will work, if not I can just solder the wire back together. I love modding the X. So far I've changed the interior lights to LEDs and I've added the back up sensor system using the stock harnesses already in the truck. Next up I'm adding heated mirrors, led turn signals on the side mirrors, a message center and hopefully the electronic climate control. Good luck with your mods too.

The headlight circuits are just behind the main switch. If all you are doing is turning on the running lights during the day, you can cut that one wire(downstream beyond where the branch is that leads to the interior lights etc), and attach an extra trigger power source, with a switch etc, low current tiny wire. Add a diode in that spliced wire(the original light wire), so that the new current you introduce cannot go backwards and reach the interior circuits.
 






The headlight circuits are just behind the main switch. If all you are doing is turning on the running lights during the day, you can cut that one wire(downstream beyond where the branch is that leads to the interior lights etc), and attach an extra trigger power source, with a switch etc, low current tiny wire. Add a diode in that spliced wire(the original light wire), so that the new current you introduce cannot go backwards and reach the interior circuits.

Sorry I'm not too good with wiring...yet. So if I'm understanding this correctly, by adding a diode to that wire, it'll keep the interior from dimming when the parking light switch is activated? What about the headlights?
 






A diode is needed to keep a signal from going back beyond the diode and upset it's function. If you add a switch and simple power wire through that switch, to the light circuit(headlight or just the running lights), that would power the lights you want, and the interior lights also. That would be just bypassing the existing main headlight switch.

If you do that exact same thing, but also include a diode on the side leading to the interior lights, your added switch/circuit will only affect the circuit you want to, in the other direction from the diode. The diode acts as a one way valve.

I ran a circuit like that exactly in my 99 mail truck, but with different circuits. I wanted to be able to power the radio without the ignition on, and I already had a special power circuit and switch to feed my auxiliary circuits(turn signals and strobes). I connected that new power source to the radio power wire, but I had to use a diode in the radio wire to keep from also feeding every other circuit of the ignition on system.

See if you can locate where the headlight wires go and meet with the interior lights. Somewhere the wires branch off from the headlight switch, to the two systems. You want to cut(and splice in both the new power trigger signal, and the diode) where the wiring has passed where it goes to the interior lights. If you do it before there, it will also trigger the interior lights(dim them).

A diode has a polarity, it has to be placed so that the power will go the one way that you desire it to.
 






A diode is needed to keep a signal from going back beyond the diode and upset it's function. If you add a switch and simple power wire through that switch, to the light circuit(headlight or just the running lights), that would power the lights you want, and the interior lights also. That would be just bypassing the existing main headlight switch.

If you do that exact same thing, but also include a diode on the side leading to the interior lights, your added switch/circuit will only affect the circuit you want to, in the other direction from the diode. The diode acts as a one way valve.

I ran a circuit like that exactly in my 99 mail truck, but with different circuits. I wanted to be able to power the radio without the ignition on, and I already had a special power circuit and switch to feed my auxiliary circuits(turn signals and strobes). I connected that new power source to the radio power wire, but I had to use a diode in the radio wire to keep from also feeding every other circuit of the ignition on system.

See if you can locate where the headlight wires go and meet with the interior lights. Somewhere the wires branch off from the headlight switch, to the two systems. You want to cut(and splice in both the new power trigger signal, and the diode) where the wiring has passed where it goes to the interior lights. If you do it before there, it will also trigger the interior lights(dim them).

A diode has a polarity, it has to be placed so that the power will go the one way that you desire it to.

Ok I see. That's a good idea. I'll be able to know which wires control what when I buy the service manual for the Explorer.
 






the interior lights on this truck have two separate circuits coming from the dimmer. one circuit controls the cluster and door switch lights, the other controls the OHC and Radio brightness. when the headlight switch is turned off, the dimmer wire to the OHC is 12volts and the dimmer is bypassed, when the headlight switch is on, the dimmer takes over and will never allow the console to achieve full brightness. to override that function, simply find the wire at one of three locations and add a toggle switch to a positive circuit and it bypasses the dimmer. those three locations are behind the dimmer; behind the radio; and behind the overhead console. if you simply cut the dimmer wire to the OHC, you will lose the display altogether. and like mentioned above, add a diode to the toggle switch just to be safe.
 






the interior lights on this truck have two separate circuits coming from the dimmer. one circuit controls the cluster and door switch lights, the other controls the OHC and Radio brightness. when the headlight switch is turned off, the dimmer wire to the OHC is 12volts and the dimmer is bypassed, when the headlight switch is on, the dimmer takes over and will never allow the console to achieve full brightness. to override that function, simply find the wire at one of three locations and add a toggle switch to a positive circuit and it bypasses the dimmer. those three locations are behind the dimmer; behind the radio; and behind the overhead console. if you simply cut the dimmer wire to the OHC, you will lose the display altogether. and like mentioned above, add a diode to the toggle switch just to be safe.
Sounds good, thanks for the info. I thought one of the resistor chips inside of the overhead display had to be bypassed in order for the display to remain bright when the headlight switch is turned on. Your solution sounds a lot more simple.
 






Sounds good, thanks for the info. I thought one of the resistor chips inside of the overhead display had to be bypassed in order for the display to remain bright when the headlight switch is turned on. Your solution sounds a lot more simple.
Contact bobflood on here and he can help you out with a wiring diagram. The wire color should be either light blue with a red stripe or red with a black stripe. Both colors were used at different times
 






I'm not sure what wires control the display dimming, but that is an interesting problem.

I too like to have headlights on, all of the time, but be able to shut them off, and have it do that automatically. I'm interested in what this turns up, which wire(s) deal with the dash lights dimming. I would prefer to use two sensors to control the systems, one for the interior lights, and the oil pressure for the headlights. The trick should be to simply remove the light sensor control of the headlights, reroute that trigger wire from the oil pressure instead. When the engine starts, the lights come on. I have the automatic lights(mirror), so the lights still stay on with the delay control too.

Well good news! It really was as simple as cutting a wire to disable the dimming of the overhead console, when the headlight switch is on. After much research and wire splicing, I've found that red/black is the wire color which is connected to the dimmer and receives power when the parking/headlights are on. I found this wire up in the overhead display and I cut it. Now the display is bright whenever the key is forward, wether the headlight switch is on or not :D The red/black wire powers the internal illumination in my 2000, such as the lights in the power window switches and the lights in the rear radio controls. I cut the wire that connects to pin #8 on the overhead display in order to get these results. But I cut the wire on the overhead display harness in order to keep the truck wiring harness intact. I plan on installing a relay to allow power to flow through the red/black wire that connects to the overhead display, whenever the headlights come on. Thus, allowing it to dim at night.
 






the interior lights on this truck have two separate circuits coming from the dimmer. one circuit controls the cluster and door switch lights, the other controls the OHC and Radio brightness. when the headlight switch is turned off, the dimmer wire to the OHC is 12volts and the dimmer is bypassed, when the headlight switch is on, the dimmer takes over and will never allow the console to achieve full brightness. to override that function, simply find the wire at one of three locations and add a toggle switch to a positive circuit and it bypasses the dimmer. those three locations are behind the dimmer; behind the radio; and behind the overhead console. if you simply cut the dimmer wire to the OHC, you will lose the display altogether. and like mentioned above, add a diode to the toggle switch just to be safe.

The solution was actually cutting a wire. I didn't know much about wiring when I first posted this, but I've learned a lot since then. It's funny how my first assumption was correct :D
 






Thanks for the update. I recall those red/black wires, that runs throughout the truck for the many lighted circuits. It's a very tiny wire, and complicated my wiring job of my 99 truck ten years ago(which had the main body harness cut(75 wires)). The memory seat in most of those models of Explorers use a same color red/black wire as the neutral/safety circuit, to disable the memory seat when the truck is in gear. It took me a while to figure out that circuit, given I had my old 93 Limited too, which uses a different colored wire, and I lost it in the dash 3-4 times I tried to find where it went. The 95+ models it has the red/black wire going to the GEM module.
 






Thanks for the update. I recall those red/black wires, that runs throughout the truck for the many lighted circuits. It's a very tiny wire, and complicated my wiring job of my 99 truck ten years ago(which had the main body harness cut(75 wires)). The memory seat in most of those models of Explorers use a same color red/black wire as the neutral/safety circuit, to disable the memory seat when the truck is in gear. It took me a while to figure out that circuit, given I had my old 93 Limited too, which uses a different colored wire, and I lost it in the dash 3-4 times I tried to find where it went. The 95+ models it has the red/black wire going to the GEM module.

It's an interesting wire. I've searched for a while for the wire that receives power from PATS when the lights flash and the alarm is activated. The red/black is one of the wires that carries current to the rear lights when this happens.
 






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