Courtesy Lights Don't work - Need help finding the problem

[MavrickMA]

Hi all!

I recently ran into an issue where ALL of my interior courtesy lights do not work when you go to turn them on individually. They all come on with the keyless entry or when you open a door, but when you go to turn them on by themselves, such as the rear cargo light, it does not work. Truck is an '03 Expy XLT 4.6L

Lights included are: vanity mirror lamps (both sides), front map lights (both sides), second row map lights (both sides), rear cargo lamp and the Homelink buttons do not work either. All others work fine.

I did some troubleshooting and it seems that I do not have power at the lamp itself, but I do have power coming out of the fuse box (assuming I tested the correct wire and I think I did).

I did recently have an issue where I had A LOT of water underneath the passenger side floormat. I had to drain/soak up at least 1/2 inch of standing water in some places, one of which was the passenger side bottom door jam where the bundle of wires goes from the front of the truck to the back of the truck. Couldn't easily find any corroded wires. Not sure of this would do anything.

Basically what I'm looking for is some advise as to where to look for the cause of the issue. There's a lot of wire in this truck and any way to cut down my options so to speak would be great.

Thanks in advance for your help!

 

[MadTxn]

Funny (or not), but I have the exact same problem on my 2004 EB. Although I attributed it to one of the items I've installed, although I'm not sure which one. At this point, I'm suspecting it might be the switch in the dash, although I have no basis for that and haven't been able to test it. Mine also will turn off if I hit the switch when they are on with the doors open.

 

[MavrickMA]

Originally posted by MadTxn
Funny (or not), but I have the exact same problem on my 2004 EB. Although I attributed it to one of the items I've installed, although I'm not sure which one. At this point, I'm suspecting it might be the switch in the dash, although I have no basis for that and haven't been able to test it. Mine also will turn off if I hit the switch when they are on with the doors open.

Same here. If your doors are open and the light is on, you go to turn that particular light on and it turns off!

What things have you installed? I've done a bunch of customization as well.

 

[MadTxn]

So far, rear view camera, hard wired V1, Viper 5900, and a Pioneer Avic Z2. At some point I'm going to fiddle with the switch. My guess is that I pulled a wire.

 

[MavrickMA]

I've got a bunch of police equipment, aftermarket stereo w/ NAV and SUB, 8500 x50 hardwired, and HID lights. That's about it. And none of it touches the courtesy lights circuit (at least to my knowledge). Any body got any ideas where I could look for the cause of the problem?

 

[ELVATO]

Maybe the switches themselves are bad?

 

[MavrickMA]

Originally posted by ELVATO
Maybe the switches themselves are bad?

Having bad switches on EVERY interior courtesy light seems pretty unlikely to me...

One or two bad switches I could see, but ALL of them? I just can't believe that.

Besides, I tested the feed and there's no power coming into the switch.

 

[MadTxn]

It seems odd that we would have the same problem and not have the same cause... I also did some wiring in the driver side A-pillar & C-pillar. Maybe something got pinched there?

 

[MavrickMA]

Originally posted by MadTxn
It seems odd that we would have the same problem and not have the same cause... I also did some wiring in the driver side A-pillar & C-pillar. Maybe something got pinched there?

I've got nothing in the driver's a-pillar, and nothing directly in the c-pillar, although I do have wires coming up from the floor and into the driver's side rear pocket (in the rear cargo area opposite the rear HVAC unit).

 

[ELVATO]

Hmm... that is weird. So they come on when the door is opened and when you unlock, right.

As far as I remember, there's three contacts to a switch light. My guess is a ground, a positive when the door is open, and a positive that's always on (this goes to the switch part.)

So I guess the constant on one isn't working.

 

[MavrickMA]

Originally posted by ELVATO
Hmm... that is weird. So they come on when the door is opened and when you unlock, right.

As far as I remember, there's three contacts to a switch light. My guess is a ground, a positive when the door is open, and a positive that's always on (this goes to the switch part.)

So I guess the constant on one isn't working.

You are exactly correct, at least according to my test light. I checked the fuse and it works, and I checked what I'm assuming is the wire for the circuit coming out of the fuse box and it works too! So I'm guessing there's a cut in the wire somewhere, or something like that. But with the amount of wire that is in this truck, how the heck am I supposed to find it?

 

[MadTxn]

I've got a wiring book at home that I *might* be able to scan. The problem is figuring out exactly where the harness goes.

 

[MavrickMA]

Originally posted by MadTxn
I've got a wiring book at home that I *might* be able to scan. The problem is figuring out exactly where the harness goes.

Hey, if you can figure it out and send it to me, that'd be fantastic! Stealership wanted $400 to diagnose the issue!

 

[MavrickMA]

Anybody else out there got any ideas? Maybe someone from Ford that's on this forum or somebody knows somebody from Ford?

Thanks!

 

[aircargoo]

OK...I JUST POSTED...OPPS caps.......anyway....i looked in ALLDATA at work and there a rpo relay box under the dash above passenger airbag

i cant get my dome light and running boards to light when door opens

my door markers lights work fine....nothing installed but a radio

location is there....but doesnt look like it...theres a box there but not messing with it just yet...

i pulled one out from a 00 expedition yesterday....theres one relay there,only 1.....according to ALLDATA....theres suppose to be same as 97....a rpo box with fuses and relays.....i dont see it...bet mine has only 1 switch or relay to....