Weird lighting problem

[kd7kmp]

Weird lighting problem---BIG UPDATE 9/20---

Okay...the fuse(s) (#4 and #15) that feeds my tail lights keeps blowing. It is mostly fuse #15 that blows. It does so when I have had the lights on for about 5 or 10 minutes. It happens whether I use the manual healamp switch or the Autolamp switch. Here's what I don't understand: the overhead interior lights are "stuck" on. The only way to get them to turn off is to pull the fuse (#8) or to unplug the RKE module in the truck. With the interior lights I know that the door jamb switches are working as well as the dimmer switch. When a door is opened or the dimmer switch is turned on the lights get a little brighter.

---UPDATE 9/20---

The dealership found that the harness next to the driver's side passenger seat has several wires with the insulation burned off. About a dozen in all. They are replacing those wires now. There was also a chaffed wire in the trunk next to the trunk hinge that had a small amount of insulation worn off. That my have been the one that caused all the problems to begin with. I also have to replace two blown diodes in my RKE module. Thanks to all for the help.

I do have one more question: do SHOs have the lamp out warning light? If mine does where is the control module for it? Thanks.

Kevin

 

[SHOZ123]

To clean the door switches spray then liberally with WD 40. Then open and shut the door several times.

 

[kd7kmp]

Where do I spray with the WD-40? The latch, handle, lock, etc? Thanks.

Kevin

 

[kd7kmp]

I have narrowed the problem down to the circuit that powers the courtesy lights. The tail lamp fuse doesn't blow when the courtesy lamp fuse is pulled out. I have run ground and power tests on the wiring and have not been able to find any faults in the wiring that powers the RKE module. I believe the problem lies in the module itself. Is there a way to test the module for any faults? This module has three plugs in it. Are there any other Ford vehicles that use the same RKE module. I plan on going to the junkyard to look for one tomorrow. Thanks for all the help.

Kevin

 

[Markus]

The RKE system connects to the parking light wiring so that the parking lights will (supposedly - mine flash only briefly) flash when either locking or unlocking the car. The connection is the brown wire (circuit #14) at pin 24 of the RKE system, and the RKE gives 12v to this wire when it wants to flash the lights.


If you start with all new fuses and turn on the parking lights ONLY (not headlights), do the fuses still blow? With the information I can help you more.

 

[Markus]

After looking at the electrical schematics I think that the RKE system is providing a high current electrical load via pin 24 instead of applying 12v to it. When you turn the parking lights on, current flows through fuses 4 and 15 to ground via the RKE system. Note that fuse 15 is inline with, and electrically after, fuse 4.

If you need the schematics I can scan them and send them to you.

 

[93SHO'nOFF]

It sounds like you might have a headlamp switch and connector problem.I've repaired several on a number of different ford models.
The connector melts apart from heat that the hdlmp switch produces when turned on ,then wires could be touching each other or have to much resistance from the bad connection causing fuses to blow.Ford had a recall for this a couple yrs back, but The only other thing that causes electrical nightmares might be a broken or loose ground wire.An easy way to check if it's a ground problem is to take jumper cable's from eng. block to neg. battery post and body to neg post. Then recheck for the concern,if the concern is gone inspect neg. battery cable where it goes on block and body.
Good Luck

 

[kd7kmp]

Thanks for all the suggestions, guys. I really appreciate it. I took it to my local dealer (the service manager there is a school buddy of mine). I just don't have the time right now to keep looking at it. I appreciate all the help. I will post what the problem was and how it was fixed.

Kevin

 

[Markus]

It sounds like you might have a headlamp switch and connector problem.I've repaired several on a number of different ford models.
The connector melts apart from heat that the hdlmp switch produces when turned on ,then wires could be touching each other or have to much resistance from the bad connection causing fuses to blow.Ford had a recall for this a couple yrs back, but The only other thing that causes electrical nightmares might be a broken or loose ground wire.An easy way to check if it's a ground problem is to take jumper cable's from eng. block to neg. battery post and body to neg post. Then recheck for the concern,if the concern is gone inspect neg. battery cable where it goes on block and body.
Good Luck

In this case I think you're wrong. I say this because of the concern of the interior lights not going off. The situation you describe above does not take this into account.

 

[kd7kmp]

See update in start of thread.

Kevin