I replaced my cruise control switch awhile ago when I tried to replace the LEDs with red ones.

I never noticed since I don't use the switches, but they only light up a little and don't work, nor does my horn.

What do I need to do before I take this truck down to the dealership? I need to fix it by Monday so I can register my truck now that I'm stateside again.

 

Are the same switches you tried to modify the switches that are installed ?

Does the cruise control itself work correctly ?

The horn, did you check the fuse with a meter ? The horn switch is hot at all times, so a meter from the pins on the back to ground, key can be off.

 

I bought switches on eBay and put them in. They light up, but very very little and don't work.

I checked the fuses, fuse #20 and #21 were blown. Replaced them, didn't fix the horn.

I went to AutoZone and the guy asked if I heard any clicking noise when I pressed on the horn and I said no, so he stated it could be the horn relay. I'm going to bring it in to see if it gets power or not.

I've punched my horn once or twice out of anger before I deployed, and it feels like there should be something behind it because the Ford logo area when I push on for the horn goes kind of deep.

 

So, horn and Cruise Control both do not work and the illumination is questionable.

Taking a SWAG, that sounds like an issue with the ground from the list of items.

The horn switch pad in the cover switches ground to the horn relay.

Pull the horn relay and in the socket, you can check if the horn pad is supplying ground to the horn relay.

The horn, pin #1 and Pin #3 are both power ( hot at all times ) from BJB ( aka Battery Junction Box, Engine Compartment fuse panel ) fuse #7 on the 2003.

Pin #2 is the ground from the horn pad. If you meter from ground to the relay socket pin #2, when you press the button, there should be continuity or 0 ohms of resistance.



The red line in the picture above you can jumper across with a section of wire and the horn should work.

If you do not have 0 ohms or continuity to pin #2 ( as long as you have a good contact with the meter ) I would either start by checking the clock spring or if the new switches are having some impact on it. Easiest to pull the newly installed switches and checking again.

You are back state side now, that you can do this ?

 

I'm back stateside now.

I took the horn relay to AutoZone and they tested it and said it was getting power because it would make a clicking noise.

My relay has a middle prong between 1 and 2.

Also, I found my old key fob, I hit panic and the lights go off but no horn. Just for your information.

 

Not sure how they can test the relay out of the truck, and say it is getting + VDC .

It should get + VDC all the time, the ground is what is switched.
- Sorry, yet another example of why Autozone is not to be trusted.

If you can get your hands on a meter to test for the ground from the horn switch in the relay socket, this is a good place to start.

The horn relay having an additional pin, Are you sure you have the correct one ?

This is what a half ISO relay looks like.
The diagram in the EVTM shows pin numbers for a half size ISO relay.




Does not mean it does not exist, but I have not seen a half size ISO relay from Ford that also has the normally closed contacts ( SWAG this is what it would be ).

 

The guy at AutoZone connected a wire to it, and touched a battery terminal and you can hear it clicking.

It was fuse #205.

I'll have to check the horn to see if it's getting power.

I'm about to just take the truck down to the dealership, but afraid of how much I'll be charged, lol.

 

Not too sure what he was probing with the wire.

The relay should not click multiple times, that indicates a problem.

If it was a + VDC triggered relay, when + VDC is applied it should click once, and be quite. If the relay clicks in and out, the coil is not holding.

This is a very Shade tree method of testing a relay, and really does not prove anything.

Relay # 205 is the correct one, for the horn.

Fuses #20 & #21 have nothing to do with the horn, not too sure what is going on there:
BJB 20 = trailer tow Left stop / turn signal
BJB 21 = Not used.
CJB 20 = Radio , PCM,GEM , Trans range sensor
CJB 21 = DTR sensor, Clutch switch, stater relay and feed for CJB Fuse #20

Try to get a hold of a meter, and check for the ground in the relay socket, to see if it is coming from the horn switch in the steering wheel.

I am still thinking issue with the ground, which could be caused by any number of things ( including the eBay switches you installed )

 

Thanks SSCULLY for the help, I ended up just saying screwing it and taking it to the dealership. $90 to check the horn, $104/hr.