1998 5.0 XLT Electrical Gremlins. PATs and horn problem.

[Nate_V8]

So the truck runs great but the electrical gremlins are a bit of a pain. I had the lock problem last year where the locks would unlock by themselves and then they would sometimes have a seizure and keep unlocking and locking but I somehow fixed that. I tore apart the back and found the box that controlled the power locks and unplugged it for awhile but my lock cylinder for the hatch is broken. So I had to plug the power locks back in and since then I've had no problems go figure and that's even through the winter.

But now.... bear with me while I try to explain this the best I can.

I noticed a few months ago that when I pushed the lock button twice there was no more honk. For some reason I thought nothing of it until I went to honk my horn at someone and no horn. So pushing around randomly on the horn i finally found a spot where if I pushed and held it for a few seconds the horn would work and then once it started working it would work normally, honk with a normal touch anywhere. And then it stopped working again and I can't get it to work at all now.

So no idea why it wouldn't work until I pushed the right spot and then it worked for awhile again and then stopped permanently now.

Now just yesterday I went to start the truck and turned over fine but didn't catch at all. Theft light flashing, go look on internet and see it's a PATS problem. Try shifting the gear level into drive and back to park. Nothing. Try moving tilt wheel as someone mentioned something about vibration and a sensor and it worked! Then after groceries it didn't start again (theft light flashing) but this time the tilt didn't work. Do some more hunting and tried turning the key on and off 8 times and leaving it on on the 8th time and pushed and held the unlock button on the drivers door. It worked. Although I don't know how it worked as I misread it and I was supposed to hold the unlock on the key fob or push every button on the key fob.

So I have a horn that doesn't work and a PATS problem. Any ideas?

Not to mention a few weeks ago my day time running lights stopped working so I crawled under, got covered in dripping water/salt and pulled the daytime running light relay from under the front bumper. Not plugging it back in either. GREMLINS!

 

[J_C]

Seems like either the switch contacts in the steering wheel or an intermittent contact and/or failing remote receiver module (or both).

PATs, seems like most people are have a problem with the coil module around the ignition cylinder... not sure what fails on those electrically unless it cracked or has a bad connection, fouled connector or circuit board solder joint cracks. You could pull and examine that module or replace it, new or a pull from a junkyard. That module itself does not have any vehicle specific programming applicable, a working replacement should be plug 'n play.

If daytime running lights aren't working, you lost me on what the purpose was for pulling the relay out and leaving it out. I'd start with measuring for 12V on the relay power-in contact to see if power is getting that far, and if so then power on the output pin to the lights. If no power that far then trace the circuit backwards, possibly a fuse or battery saver relay?

 

[1998Exp]

...
If daytime running lights aren't working, you lost me on what the purpose was for pulling the relay out and leaving it out. I'd start with measuring for 12V on the relay power-in contact to see if power is getting that far, and if so then power on the output pin to the lights. If no power that far then trace the circuit backwards, possibly a fuse or battery saver relay?

I believe that by "DRL Relay under the front bumper" the OP meant the DRL module. They are rare in the US, but he is in Canada. These are known to fail, showing a host of symptoms, from loss of the the DRL function (turning on high beams on reduced power while engine is running, parking brake not engaged, and headlights off), to high beams not working, to false activation of brake warning light, etc. Removing the module solves the problem, except that to comply with Canadian law, one must remember to manually turn on the headlights (hopefully on low beams...) while driving.

 

[CDW6212R]

It sounds like some disconnection in wiring, I'd start in the Driver's door jamb. It's somewhat common to have one or more wires break in the section on the car side. Take off the boot covering it there, and the 10mm bolt holding the two halves together. The door lock wires go through there, and if any are broken, or shorted together, that could cause the lock issue. The PATS wiring around the ignition key cylinder is fragile, the tiny plastic tab holding the receiver can be broken, letting the parts get away from the key, thus an error.

Check wiring in general, main power and ground wires under the hood etc.

 

[Nate_V8]

The door locks aren't a problem, they've been problem free for about 8 months now (knock on wood). I was all ready to tear apart the door jam behind the driver seat as I read on here that it a prblem spot for the door lock malfunction I experienced. But afer I plugged the RAP module back in I haven't had a problem....knock on wood again!

The DRLs malfunctioned and stayed on after I shut off the truck so I unplugged the relay and no it doesn't have the limited model delay in the rear view mirror in case anyone asks lol. I've owned 9 foxbody mustangs and all were before 94 (when daytime running lights became standard in canada) so I'm used to turning on my lights when it is cloudy and I still do it anyways because daytime running lights are for the head lights only so on a cloudy day I turn on my lights so my tail lights are also visible. Not worried about the module as I know how to fix it if I ever need to. I like how you hope I drive with my low beams on during the day and not my high beams... I'm not an asshole lol. Who turns on their lights during the day and then their high beams also? Here in montreal I only see people forget to turn on their lights at all at night because I guess their daytime running lights are enough so they can see with the street lights also,,,,except no tail lights. Always satisfying when a cop nails them.

So the turn off and on 8 times didn't work so I tried just turning it off and on until the theft light went out and then when it finally started the theft light turned on with the truck running and stayed on solid for about 20 seconds and then started blinking while I was driving, about 1 per second. Then when I shut it off the theft light stayed on solid and didn't blink every 2 seconds. I came out a few hours later and it was blinking every 2 seconds like normal and I did the on/off 8 times and that worked. By the way every time I do the on/off 8 times the locks unlock twice.

Any ideas as to why my horn would not work and then work after pushing really hard on the center of the steering wheel (which then once it worked again I could push anywhere lightly and it worked) to not working again (the pushing hard trick doesn't work now lol)? Seems weird I have 2 possible problems around the steering wheel/column.

 

[CDW6212R]

All of the wiring for the steering wheel goes through the clock spring, all of those wires are very fragile. It sounds like wiring or damage to something in amongst it all, such as the PATS receiver. How often has the column plastic cover been off?

 

[Nate_V8]

I don't know. I've owned it it for almost 2 years and it has 140k KM on it. I've never had it off since owning it. Does the PATS wiring go through the clock spring or is it below the clock spring?

 

[delexploder]

The module in the back that has the number code on it can go nuts and cause this , mine did

 

[CDW6212R]

I meant the wiring in the steering wheel, yes the PATS wiring goes underneath. It's all very small gauge wiring, any time that cover comes off, someone may hurt something easily. My Mercury had the PATS receiver mounting tab break off, I discovered it by the engine randomly not starting. It took a year to trace the issue, and simply RTV it in place.

 

[CDW6212R]

Ditto, lot's of potential gremlins, you like to begin with simple wire connection breaks etc.

 

[Nate_V8]

The module in the back that has the number code on it can go nuts and cause this , mine did

I don't think the RAP module in the back is causing this issue, it (or the wiring to it) was responsible for my lock problem though.

I guess I will have to take apart the steering column and see what is happening. It better just not be a failing battery lol

 

[J_C]

Failing battery would tend to cause slow cranking before anything else.

 

[Nate_V8]

Alright so I did some hunting and found some sketchy wiring.

I circled everything important in red.

Here is a wire just hanging out, no idea what it goes to. white with a blue stripe.

(ok I forgot to circle this one)

I believe that wire goes to the white wire that is looped. again no idea what it goes to. Also found that black wire just hanging right where it was behind the dash panel. I couldn't trace it either. There is some kind of trailer controller hooked up though that has a on/off toggle switch also. If anyone knows the wires well let me know!

What is that box? It has a flashing light, is it an after market alarm system or is that stock?

Side note: Found that hanging in front of the rad. could see it from between the bumper and grill, it is about 1/3 up from the bottom of the rad, couldn't see any hole it is supposed to go into but looks to be a temp probe. Not too worried about it or else my truck wouldn't be running! Just really weird

Found the PATS sensor, has a minor(or major?) crack.

The brass contact is bent over and you can't see it very well but where I circled in red there is a wee little tab broken off. it did move around easily when I first prodded where it was mounted which I'm assuming it isn't supposed move easily and pulled it out easily to boot.

What does that spring go to??? Just above the tilt level it was hanging there.



As for my horn, I took the air bag off but everything looked fine. put it back together and no horn still. Opened the hood and tried the horn and I can hear the relay clicking. So either the relay is dead or the horn is dead. Where is the horn? I have a 98, it is not in front of the rad, that is how I found that probe.

 

[toypaseo]

is that black brain with the 10AMP fuse in it connected to that brake controller via that twisted red and black wiring...?

that wiring job is scary...

 

[Centaurus5.0]

that wiring job is scary...

Your understatement has been duly noted...

 

[delexploder]

Can you pull that box out and get pics of both sides?

 

[CDW6212R]

The scary part is the main ignition wires that have electrical tape on them.

The small black module is likely a remote starter, or you mentioned trailer brake controller(I think those are larger though). I'd take the tape off of the ignition wires, and see if someone cut any of them. If the copper strands are all intact, I'd remove the added wires and reseal the wires to protect them. There are plug in wiring adapters which work much better to access the ignition wiring.

You're right about that thing in front of the radiator, that's a temperature probe. Some models have two, for the EATC etc. They just have a plastic clip on their side that plugs into a hole on the support.

The horn is under the battery, look in the wheel well to the outside of the ABS wires. They are mounted below the metal, beneath the battery.

The PATS key code receiver is fragile, but if it's intact, you can just use RTV to adhere it in place. Mine had the blue plastic clip broken off, and I RTV'd it about 12 years ago.

 

[Nate_V8]

Ok lets break this down a bit.

1. Does anyone have any idea where that spring goes?


2. Yea I discovered it is the ambient air temp sensor after I posted the pics and found where it is SUPPOSED to be plugged into the support, I will try to get it back on there instead of hanging close to the hot rad, although I'm assuming it has been there a long time haha

3. So that black box isn't stock by everyone's reactions. Sigh. Ok I will try to get it off and get some part numbers. I HATE wring and find **** like this intimidating. I don't think it is causing the issues to my problems (horn/anti theft) but I'm assuming that it could cause problems in the future... Like fire...lol

4. So to access the horn I need to remove the battery tray? I think I found it but couldn't access it through the wheel well. If I hear the relay clicking does that mean it is ok? Definitely getting power if it's clicking when I push on the horn. I really hope the horn is it just dead or something but I feel like I won't be that lucky and it will be some kind of screwed up wiring somewhere between it and the relay...

5. So that blue clip has something to do with the PATS? Because I looked up pats transceiver ring and the replacement part had no blue clip. It was the little box behind it and a ring around the ignition that blue clip was plugged into. That blue clip looked like the wiring went into a thicker bundle with a solid yellow sheath and went down the steering column. Does not look to be plug and play. Do you happen to have a pic of an intact one? I can't find any pics, I don't know if the metal tab is supposed to be bent on it or what you mean when you say you you RTV'd it in place. Is it not supposed to move at all? What a PITA!!

 

[toypaseo]

I dunno if this helps for the spring...

 

[boominXplorer]

That blue clip is for the key minder (door dinger). The big black ring behind the key with the little box attached and green wiring plug going to it is the pats receiver.