Truck goes crazy when key is out of the ignition, Instrument cluster goes on and off, beeps, ...but I don't think it's the actual instrument cluster.

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Evox

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The problem started again this morning. I'm at wit's end. I have the new Motorcraft key cylinder arriving tomorrow. When I change it out, I will take another look at the ignition switch and reexamine the plug and the wires attached to the ignition switch.

I feel like I've checked every possible ground wire. I've checked continuity and every plug I can find. I've cleaned everything. This is a southeastern truck, so corrosion isn't a problem. I did find a smashed wire leading to part of the EVAP system, but I don't see how this could be the problem. I checked all the wires leading from the driver's door to the body and can find no worn or broken wires. I haven't cut away the insulation for the harness leading to the fuse box in the engine compartment, and I guess there could be something broken there. But I don't see how the insulation looks good.

Maybe this is it for the old girl.
 

Evox

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The problem is back. But is REALLY intermittent. Lasted almost two days without acting up. Oh, and it's been parked the whole time, so...


The only thing I can be absolutely sure it's not.
-battery-good
-alternator-good
-ignition switch-new (now I'm just throwing parts at it)
-ignition switch plug-inspected, checked, and good, put a new seal on the ignition switch plug, connected to switch, and torqued to spec.
-ignition key cylinder-replaced new (more throwing parts at it)
-headlight/driving/parking/dimmer switch-replaced new (still more parts being thrown at it)

I've gone through every fuse/relay/diode; all test good, no short found. I've checked plugs for corrosion, used electrical cleaner everywhere.

When the instrument cluster is going nuts, and by nuts I mean it beeps, the odometer flashes XXXXXXXXXX then goes to faint dots and dashes ...,.........., sometimes the message center flashes "Check gauges," sometimes "Low Fuel." If the radio is left on when the truck was turned off, it joins in on the fun and comes on for a few moments, as do the cabin lights if the dimmer switch isn't turned all the way off. I can hear various relays clicking open and closed...then everything goes off and settles down.

Except the faint dots and dashes .............. on the odometer. But sometimes those go off as well. Sometimes it stays off for minutes at a time; sometimes, it cycles through over and over again. Sometimes it just beeps and does the XXXXXXX on the odometer; sometimes, the "Check Gauges" or "Low fuel" message stays on. Sometimes, it doesn't. Sometimes all of this goes off for long periods of time, only to start over again.

Checking for parasitic draw using my multimeter, nothing comes up a couple of hundred milliamps.

I think it's time to burn this truck up or part it out. I'm frustrated and sick of this crap. I'm going to pull the dash cluster and look for cold breaks under a magnifying glass, but this is power being BRIDGED to somewhere, not broken. And again, when the truck is running, everything operates as normal. No electrical problems, no system problems, and no codes being thrown.

Does the instrument cluster circuit board have switches or maybe diodes on it that are malfunctioning?

I checked for broken or frayed wires in the harness from the body to door and could find none. BUT my driver's lock switch is dead. I don't think that's the problem because when I pull the fuse for the door locks, the cluster still goes nuts. But I remember reading something about the driver door switch causing weird problems. The search function on the website doesn't seem to be working, or I can't get it to come up with anything.

Can anyone point me in the right direction?

Edit to add: This afternoon, I took out the ignition key cylinder again. made sure I cleaned all the contacts, and so far, no problem. The way this has gone, I'm not hopeful that somehow I fixed it. The cylinder seemed clean. Also, this is a southeastern car, so corrosion isn't a big problem.--so maybe it was the ignition switch or lock cylinder. I used the Motorcraft lock cylinder kit on the lock cylinder so I wouldn't have to re-key it. It's a fairly simple procedure, take your time, and you should have no problem.
 
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Todd Z

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you could have a relay with a failing spring, something getting wet, or something else. As far as a joint disconnecting, relays work in funny ways, Normally open or closed. Could be a relay loosing a Call signal and closing or opening... Time to disconnect stuff at night and see what helps, then work your way back.
 

Evox

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You're right; it could be the cluster. ...again. Manifesting the weirdest cluster problem I've ever read about.

One where the truck's electronics and gauges are absolutely 100% flawless when driving or when the truck is running.

One that ONLY manifests itself sometimes when the truck is off by actually energizing things. If it's the relays, more than one is faulty because I've switched them around. There are only two different relay types in this truck.

I wish there were some way I could narrow it down to the cluster or PCM. I know it's not the battery or alternator. Both check out fine. The battery holds 12.65 volts and never goes below 10.5 volts when cranking the truck. So is normal. So the battery has both voltage and cold cranking amps. The alternator starts charging around 14.1% when the truck is started and declines from there. So the alternator diode is working fine.
 

Todd Z

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Just unplug the PCM over night..... or the fuse for it.... Same for cluster....
 

Evox

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I'm now guessing it's not the PCM; it's the cluster. I caught it this afternoon, and while it did its thing, I got through every relay and fuse in F1 and F2.

Fuse 2-25 (Cluster, 4x4 module) stops everything - which cuts all power to the gauges and message center. I guess it could be 2-26, 2-27, or one of the other fuses feeding the cluster, but pulling those didn't stop anything. Only Fuse 2-25 worked.


So it's probably the instrument cluster or a short-to-ground along G300's path. But G300's mounting point looks pristine. The ground wire and the wire bundle all look good and fresh, and G300 grounds a lot of stuff, so it'd be really unusual only to cause a fault in Fuse 2-25 without it just being some bizarre circuit board problem. So, I'm not hopeful this a simple ground.

More than likely, it yet another bizarre manifestation of the instrument cluster failure. This really is a pain, and one I don't understand since this one actually only energizes after ignition is off. In comparison, driving no faults, no flaky gauges, nothing. Only when off does this one come to life. I've scoured the internet to find another example of cold breaks or faulty instrument clusters causing this kind of error and can find none. Most manifest while driving.

Fuse 2-25 is one of several fuses to the cluster and looking at the wiring diagram. It could be a lot of stuff because Fuse 2-25 is one of the few on my RWD Sport Trac that goes directly to the cluster (no 4x4 module to worry about). So I'm guessing it's the cluster again. Maybe I'll get lucky, take the cluster out, and find a cold break I can resolder something obvious. It's just that this makes absolutely no sense to me unless it's not a cold break, and instead, it's a bad diode, switch, or microprocessor on the board. ...that's way above my pay grade.

It could be F2-25's wire leading to the cluster plugs. But after tearing apart my wiring, I don't think that's likely. The max draw during its glitching is 1.4 amps, so not enough to blow Fuse 2-25, which is 7.5 amps. It's also a strong indication that it's not the PCM, which I think draws 3 amps on start.

The wires just on a causal look all look good. I guess there might be an outside chance that one of the relays in the Auxilary Relay box is faulting in a closed position. But it's not in F1 or F2; all those fuses and relays check out. I don't think Fuse 2-25 powers any of the relays in the auxiliary relay box, but I'd need to do more homework to rule one way or another. There is an outside chance it could be one of the auxiliary relays. Or, perhaps one of the fusible links...but I don't think so.


PS: Everything I just wrote may sound like I have a handle on this. I don't. I'm open to suggestions and ideas. Thanks.
 
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Evox

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Check my math.

-pulling the PCM relay and fuse does not eliminate the draw or malfunction.

-I verified today that G300 (ground wire behind drivers kick plate) is as good as it looks.

To make sure F2-25 is THE only problem, I reinstalled the fuse and noted a 650 milliamp battery draw at the battery (I don't know how I missed this before). A spike followed this, and then a constant 1.5 amp draw as various relays clicked closed (energized). For short periods of time, even higher (I know I saw 5 or 6 amps momentarily during a malfunction event) but only for a fraction of a second. Those spikes were hard to determine because they were very short in duration and transient.

-leaving in F2-25, I then individually pulled out F2-26, F2-27, F2-28, F2-29, all fuses going to the cluster; nothing changed the draw, spike, or malfunction.

Next, I wanted to try to find out which relays where were involved. So I systematically pulled relays one by one to see if I could eliminate the amp spike; none of them did that, I could still hear a relay clicking somewhere. But it doesn't appear to be in F1 (fusebox in the engine compartment). It sounds like it's on the driver's side, but my ears aren't good enough for me to be sure.

So I think I can be fairly confident that the trigger is F2-25 which goes to the cluster, 4x4 module. And since my truck is a RWD, that leaves F2-25 to the cluster.

So, in my opinion, this is the instrument cluster, and because of the draw unlike my last cluster problem, and most cluster problems, this one does very much look like a short of some kind.

Does my math check out? IS there something else I should look at or eliminate?
 
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Evox

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I'm still open to possibilities.

The fact that the cluster performs 100% while the engine is on makes me reluctant to conclude this is just another instrument cluster failure. I've experienced the typical cold brakes, and this isn't it.

Something is energizing the cluster when the truck is off. So I've torn through the electrical schematics, and because I'm such an amateur, I'm having trouble finding other possible causes. I'm completely open to any suggestions.
 

Evox

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Pulling the PCM fuse didn't do anything. The only fuse that stops the problem is F2-25. F2 is the fuse box inside the driver's side door. Fuse 25 is always on and runs to the instrument cluster. The truck will run with F2-25 pulled out, and checking the battery, the alternator will charge the battery despite the instrument cluster off. But you lose the instrument cluster and radio. I haven't driven it with this fuse pulled because while driving, there are no problems. It's only when the truck is off that the instrument cluster comes alive.

If the instrument cluster repair folks energize the clusters to test them, I doubt they'd find a problem. I'm out of ideas.

I guess I'll have to find a mechanic that is good at electrical systems to diagnose this problem before I throw another instrument cluster or PCM at it.
 

Evox

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Today in frustration, I jiggled the ignition key without the key in the ignition. It seemed to affect the glitch behavior. The more I jiggled the locked ignition cylinder, the more the odometer flashed, the more it beeped.

1. I replaced the ignition switch
2. I replaced the ignition lock cylinder

So, maybe the ignition actuators are the problem? Maybe there is something worn or broken in the steering column? Ideas?
 
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