Can't think of one. Drive it and let us know if you encountered any issue(s).

 

On a basic work truck, I am not sure that it really does anything important..... worst case, your chime may not work...... I know, tragedy, right?

 

You have a chime the older trucks had a annoying buzzer.

 

As we all know, the CTM makes noise for:

• Door open
• Headlights on
• Key in ignition switch
• Driver's seat belt not fastened

It also supplements the:

• Airbag warning
• Check gages
• Low fuel
• Low wash
• Trans temp
• Water in fuel (diesel models, obviously)

If you're up for diagnosing:
CONTINUOUS CHIME WITH HEADLAMP SWITCH IN OFF POSITION --AND-- KEY REMOVED FROM IGNITION CYLINDER

Cause 1. (As you already mentioned) Key in ignition switch sense circuit shorted.

Fix: With the instrument panel wire harness connector (Connector C1) for the headlight switch, the instrument panel wire harness connector (Connector C2) for the ignition switch, and the instrument panel wire harness connector for the CTM all disconnected, there should be no continuity between the key in ignition switch
sense circuit and a good ground. Repair the key-in ignition switch sense circuit, if required.


Cause 2. Faulty CTM.
Fix: Replace the faulty CTM, if required.



 

Reviving this....
Replaced the CTM as suggested in the service manual/troubleshooting.
No change, still chiming SLOW as soon as the harness is connected (again- no key in ignition). As I think about it- the suggested troubleshooting for a shorted key in ignition sensor does not apply here (I think...)
Key in ignition chime is the FAST chime that we typically hear when we do that, or leave the headlamps on and take the key out. The slow chime comes from the EMIC- and as I read this section it occurred to me that I don't recall ever hearing a chime for low fuel, or low washer fluid as it's supposed to do ( or it's been so long I don't remember it). The lights for both illuminate on the dash, but no chime.

Seems to me that if the key in ignition sensor were shorted, I'd get the fast chime as that's the default- not the slow one

As Hey You stated, I've been driving with the module disconnected just fine and figured eff it- until this morning when I was driving 60 miles in light rain and discovered that the CTM also provides the timing for the intermittent wipers. So, it was constantly switching the wipers on/off- or just leaving them on wiping a mostly dry windshield.

For no reason other that being able to have intermittent wipers I'd like to figure this out, but there's no suggested troubleshooting for this.

 

I would test for the key sensor anyway..... Probably be easy to leave the door open, stick the key in, and see what happens.

The CTM thinks something is up...... question becomes, what???? Are all your gauges reading properly? All the lights working? (in the cluster?)

 

I've been staring at the wiring diagram and there are some interesting design decisions. In any case with the truck dinging and key out, remove fuses 6, 11 and 13 individually (not all together) in the inside fuse panel. 13 should definitely stop the dinging, the other two might give some clues if there is something wrong with the signal from the ignition switch.

 

It isn't clear to me that the key-in sense can be eliminated from troubleshooting, regardless of fast or slow chime.
You've attempted repair for CAUSE 2, but not for CAUSE 1. If there's a problem at the switch, it's going to chime.


If the low fuel and low wash lights are on but there's no occasional ding, there may be a fault with either or both of those circuits since you should get a constant light and occasional ding until fluids are added. My '01 only dings once now and then under these conditions, not a steady chime as yours is doing. For now, get the wash fluid level up with enough water to turn off the light, key on, and use the washer switch to pump out the water and see if you get a ding and light when the water level gets below the jug's switch. If you get both, move on to testing the low-fuel with real-life conditions, with a can of gas in the bed of your truck, just in case. I have no idea how low fuel gets before the warnings. Start by adding just enough gas to turn off the warning light (probably just above 1/8th full), drive normally until low fuel warning. Light & ding?

True if it's shorted to the fast chime, not true if it's shorted to the slow chime. But I don't know if that's even possible.