I do know that the light switch was not working perfectly. When I would turn it to the parking lights, nothing happened. But when I turned it to headlights, all the lights would work perfectly. So that was a sign the switch itself was not working perfectly. Also, the dimmer switch did not work perfectly as well. Usually, when you rotate it up all the way, you should feel a little click, turning on the indoor and bedlight (from the third brake light) on. But my dimmer switch did not do that. Could it be a combo of this that caused this? and me splicing the LB/RD wire with the OHC wire was just a temporal coincidence?

 

The main light switch sounds like a possibility. It is supposed to switch the headlamps on a separate set of contacts from the parking lights/interior lights. Maybe the circuits are crossed inside the switch and that was allowing the headlamp circuit (30A fuse) to power the interior circuit (wire sized for a 15A fuse). However, that still doesn't explain what was actually causing the high current draw on the LB/RD that made it melt.

 

Well, what I do know is that I have to replace that wire (or the entire wiring harness), replace the dimmer and headlight switch. And if and when I accomplish this, I will wire my OHC to another power source (I may need help with this too).

 

The LB/RD is not the console's power source. It is just used by the console to detect when the parking lights are on so that it can dim the console display. The current draw by the console on that wire should be miniscule.

 

I really didn't think it was the OHC wire, because it worked fine during the day, I even calibrated the OHC and it was working perfect. It was when it got dark, and I had to turn on the headlights, all of a sudden I started smelling something burning, then one block from where I started, the truck died. I tried to restart it 2 or 3 times without success (maybe trying to restart it really fried the wire?). So logically speaking, I really think it was some fault with the lighting system, and not what I did (installing and wiring the OHC).

 

no fuses= a nono.....heres part of what i got mine wired to...to 2 20amp fuses that arnt labled are the driver and passenger seat...seperate....this is a secondary fuse panel that i put in and its supplied with a 8ga wire from the battery (inline fused aswell..) invest in one of these dude....like 10-15bucks from advaqnce auto parts

 

If the above is true, I'm not sure why it needed to be fused? And I never claimed to be an expert in electrical wiring, I only mentioned I've done some work before and would most likely not make obvious errors like confusing a ground wire with a live wire. But I do admit I can make errors. I really like that set up (DUB) that you have, I will definitely keep that set up in mind when I add any future goodies.

 

The factory wiring for the LB/RD in the Explorer w/console is exactly the same situation as adding the overhead console to a Ranger. The 15A fuse is in the underhood distribution box and it protects the exterior light circuit which has a branch to the dimming module that feeds all dash lighting including the radio and overhead console. There is no intermediate fuse.

 

"The LB/RD color code originates at the dimming module and is present only in the interior to power the dash illumination.

The color code of the feed to the dimming module is solid brown and it comes either directly from the main light switch or it goes through the park lamps relay on the way. Trucks with a RAP module (for the remote keyless entry) are the ones that have the park lamp relay. With RKE, there is also a short WH/BK wire between the headlamp switch and the relay. All of this is still in the interior, of course.

Tracing the circuit upstream from the main light switch, the color code for the parking lamp circuit is tan/white. This is the wire that passes through the bulkhead connector in the firewall. It is fed directly from fuse #11 (15A) in the engine bay distribution box."

I am looking through my haynes manual at the wiring diagrams and can't find what you are describing. Can you recommend a repair manual that has better wiring diagrams? OR which manual are you using? By the way, I do not have remote keyless entry, I do have power locks however (if this means something).

 

I guess what I need to know is where does the LB/RD wire go to (each plug/ component), and how do you introduce a new wire into the existing plug? DO you solder it in? DO I have to cmpletely remove the old wire from it's position in the plug, etc.?

 

If your truck has factory power locks, then I'm reasonably sure that you also have RKE. If you got your truck used, the RKE fobs may not have not been included. You can get the correct fobs on eBay and program you RAP module to accept them.

The best wiring schematics are in the genuine Ford dealer wiring manual, known as the EVTM in 1998. You can buy it from Helm, Inc. for about $50~60 new or you may be able to find one on eBay for $10~20.

 

If you trace the LB/RD from the dimming module, it splits and goes to many places under the dash. You would need to pick out the melted branch(es) and replace the wire or wires as necessary. Solder and heatshrink tubing would be my choices for a reliable repair.

If the damage goes into a connector, I would try to use replacement connector pins (often difficult to find) or bypass the OE connector by using a single-conductor external connector for the damaged wire.

Also, Motorcraft sells a variety of repair plugs and that might another be a way to go. They aren't cheap, though.

 

Where the LB/RD wires go from the dimming module:

 

OK, so I got a new dimmer switch and headlight switch. I had to totally rewire the LB/RD wire system (used the EVTM as a reference). Kept all the same connectors. The only wire fried was the LB/RD going from the dimmer switch to the radio. I had to separate the wires that were close to this wire (because this wire melted some of the surrounding wires slightly). I found that the fuse for the fuel pump relay/ RAP was gone (#9 in the power distribution box). Also, the #20 fuse for the RAP/GEM/Radio in the "in cabin" fuse box was blown. I replaced these fuses, put everything back together, and then crossed my fingers. The truck started perfectly, the lights work perfectly along with the dimmer switch and all the positions for the light switch.

HOWEVER. Now the #20 fuse keeps blowing out, and my radio and ohc display don't work. So, I crack open the EVTM Book and follow the wire that leads from the #20 fuse. I figure the BK/PK wire was some how melted by the LB/RD in the main wire bundle behind the dash.

So, I totally rewire the BK/PK wire sysem. I run a new wire from thew back of the fuse box from the #20 fuse and run it to the GEM module, I splice a wire from this wire to the Radio to serve as the YW/BK wire, and I find the BK/PK wire that was originally spliced to the BK/PK wire that goes to the RAP module. I splice this wire to my new wire representing the BK/PK wire. I give myself a pat on the back, and I go ahead and replace the #20 fuse. I hook up the battery and turn the truck on. By this time it's dark outside (started this project at 9am). Well, the #20 fuse blows again. And now I realize that my brake lights (including the third brakelight) don't turn on when I press the brakes. Well I wrapped everything up and called it a night.

So, (Bob if you're out there please reply) what is the next step?
The only thing I can think of is the wire running from the splice off the "new" BK/PK wire to the RAP module (this being BK/PK as well) was somehow melted in the main wire bundle by the LB/RD wire. So, should I run a new wire from the splice to the RAP module? I would like to just splice the new wire to the BK/PK wire going to the RAP as it travels from behind the driver side kick panel before it goes under the carpet to the rear of the cabin to the RAP module. Unfortunately I looked at this bundle and my luck, there are two BK/PK wires in this bundle. Any ideas on which is which? Could it be something entirely different that's blowing the #20?

I still don't know why the brake lights don't work. I didn't bother to recheck any fuses because it was late and dark. I'm gonna sleep on it and try again tomorrow possibly. Any help from anyone would be highly appreciated.

 

Sounds like you have #20 figured out. It is hot in RUN and ACC, so it is a key on power wire to the RAP module, GEM and radio (and now the console, too). To figure out which is blowing the fuse, you could try disconnecting all 4 of the loads, installing a new fuse and reconnecting them one by one. If it blows with them all disconnected, you almost certainly have a grounded wire in the harness somewhere.

The wiring manual doesn't show the exact harness routing on your 98 but my guess is that the other BK/PK is the switched power for the backup lights. You can monitor the wires and see if one goes hot only in reverse (key must be on).

 

"You can monitor the wires and see if one goes hot only in reverse (key must be on)."

How and with what do I monitor the wires. Do I actualy cut into the wire to see if it is hot when in reverse? Is there a special meter or probe for this? Thanks Bob for responding by the way. Will try the add components till it blows technique to figure out where the short is.

 

If you can find a connector and open it up, that would be the best place to check, IMO. I have also seen professional techs push a straight pin through the insulation as a quickie tap to test wires. This strikes me as a bad idea on an exterior wire that might corrode later but might be acceptable in the interior provided that it is properly taped afterward.

 

It was the OHC wire to the YW/BK that was grounded somewhere. That was blowing the #20 fuse. I used your techinique to find out what was shorting out. So I fixed it. But I'm still having the problem with the brakes. The brake lights don't turn on when I press the brakes (including the third brake light). The tail lights do turn on, but when I apply the brakes, nothing. I checked every single fuse in the power distribution box and the "in cabin" fuse box. All fuses are intact. I looked at all the relays in the power distribution box, and they look fine, but I really can't tell if they're ok just by looking (they're solid). Any help/ suggestions would be highly appreciated. And thanks Bob for all the help so far.

 

There are no relays involved with the brake lights, so that's out. The brake light circuit is protected by #13 in the dash box which is fed from the large #1 50A fuse in the underhood box. If you are getting power through the fuses, then that narrows it down to a few possibilities:

• All three of the brake filaments are burned out - not likely but stranger things have happened.
  
  
• The brake pedal position switch is unplugged or faulty (this one is a good possibility because of all of the recent work under the dash).
  
  
• An open somewhere between the BPP switch and the brake lights.
  
  There is a large 84-pin connector under the DS of the dash that carries the dark green and light green brake light wires. This is a bolted connector and it is not likely that it is the problem but worth a look. I don't know the exact location because it does not exist on my 2003.
  
  There is another connector that runs from the chassis up through the floor directly below the driver's seat. It feeds the rear brake lights and can sometimes have probelms with water/corrosion inside because it is exposed to water spray from the road.
  
  
• A combination of 2 or more of the above.

 

Hey, with your advice about getting the EVTM and your extra advice, I was able to bring my truck back from the dead. I just wanted to mention this to those that are following this saga. I invested not only in the EVTM but the two volume Workshop manual as well from Helm Publications. I recommend these books to anyone who works on their truck. These books (total cost to me was about 150 bucks) have literally paid for themselves in the labor costs I have saved doing these repairs myself. Just a helpful hint to those who don't know. I'm gonna try your advice about my brake lights later this afternoon, after work.

 

And some Texas Barbeque.

It was the BPP switch.

Everything now works like new!

Thanks for your help. This definitely was a long journey for me.

Thanks for everyone's input.

Gonna watch UFC now. Go Tito!

 

Good deal, Juan! Glad you got it fixed!

 

Glad you got it working now! and yes BOB IS THE MAN, he helped me out with my power conversion over the summer, lifesaver indeedy..