12valve@heart

Well, with over 303K miles on it, I knew that sooner or later I'd start having some problems.

Long story short, yesterday while driving down a very rough highway, I noticed an unusual smell that I couldn't identify. About an hour later, on the same highway, the Brake, WIF, & WTS lights all come on at the same time. I pull over and check under the hood - everything looks normal. I switch the heater control from Defrost to Off and the lights go off. Heat, vent, or defrost positions make the lights come on (didn't try AC) and heat OFF make them go out so we finish the trip (2 more hours) with no heat.

Arrive at our destination and turn the truck off and discover that the key tumbler will shut the truck off but doesn't want to go to the lock position to let me remove the key. Wiggle it some and finally get the key out. Restart the truck later and try things again and determine that the lights don't come on with the heat on but the blower motor isn't running (fan switch started acting up last summer and I haven't pulled it to fix it so just had it wiggled into place to run on high) and the ignition key tumbler still binds when trying to remove the key. Also noted that the message center lights would flash on when the key was in specific positions as I tried to remove it. Of course, all of this happens while towing a 35' travel trailer 800 miles from home and today it's raining all day.

Speculation - I have not done any troubleshooting yet due to the rain and much of this is speculation but here is my theory.
- The ignition key tumbler is wearing out due to age and too many keys hanging from it. I may end up having to leave the key in it but as long as it keeps the steering unlocked and triggers the start and run cycles on the ignition switch , I should be able to get it home.
- The message center lights are coming on when the ignition switch is not fully in the run position. Probably not an issue and will go away when the key tumbler is replaced.
- The smell preceded the other problems and may be due to overheating wires which are related to the fan motor drawing too many amps through the steering column.

The only problem with this theory is that it does not account for the message center lights going off when the heater controls are switched off.

Anyone care to help revise my speculation while I wait for the rain to stop so I can do some actual trouble shooting? I just need to keep it functioning safely to get us home and then I can spend time tracking it all down.

MBolivar

Jay, here's my 2 cents: Sounds like the ignition switch has gone South and the lock cylinder is on it's way due to wear and tear. A new switch and lock cylinder should run you between $80 and $100. Only small inconvenience is you'll have two keys when you switch the lock cylinder; one for the door and one for the ignition. There are 3 T-20 SECURITY screws holding the ignition switch. They're the ones with the little 'tab thingies' in the middle of the torx. My main concern is if you do decide to 'limp' home, be very careful that you're steering doesn't lock up on you with a faulty ignition switch as there's a lever that holds the lock tabs open when the key is on. Also, the lock cylinder has to be in the "ON" position when you install it into the ignition switch. It goes in a funky way and then it will lock when you rotate it to the "OFF" position once inserted into the switch itself. You'll see what I mean if you buy a new switch and lock cylinder; look at the two and their relation before you mate them. Lastly, just snug those T-20 security screws because the aluminum is soft and they will strip easily. Ask me how I know. Hope this helps you in any way. PM me if you have any lengthy questions.

12valve@heart

Thanks for your input Matt.

I took it for a drive this evening and everything acted normal except for the blower motor so the ol' girl may be willing to cooperate and get me home. Time will tell.

I'm assuming that in addition to the suggested ignition switch problem and the suspected lock tumbler problem and the known blower motor switch issue, there is probably still some other problem causing the message center lights to kick on when the heater was on or why would they go off when the heat was turned off if they were just a symptom of the ignition switch problem?

wannadiesel

Jay, that sounds like a grounding issue to me.

93DodgeRam

12vv:
I had a starting problem that ended up being a broken lock cylinder. A piece had broken off of it where it engaged the ignition switch so that the lock cylinder would not rotate the switch properly. The lock cylinder body looked like cheap die cast metal. I agree with Matt, based on this experience, that this is a good place to start looking.

It might be possible that, due to an ignition switch problem, the ECU is losing power causing the message center lights to cycle back on. I have no ideas regarding the other problems.

I hope you find the problem before you have an electrical fire.

12valve@heart

Thanks 93DR. I had considered that the ECU may be losing power but my tach never quit and I know that it runs through the ECU so the power wasn't lost for any length of time and the message center lights stayed on for a good 5 minutes or more before I figured out that turning off the heat shut them off too.

I'll probably start by fixing the ignition tumbler which I know probably has a problem based on how it felt yesterday. While I have that apart, I can check for wiring issues in the column. I know that there have been toasted wires in there before because I've had to fix them. Then I guess I also have a good excuse to implement Jim Lane's blower motor relay fix and fix that blower motor switch. We'll see what happens after all that is done.

Wanna, any suggestions on which grounds to start checking?

I'm hoping for no electrical fires either but I do carry a 10# CO2 extinguisher that I hope I never need.

torquefan

There are two common problem areas where I would look first, and it sounds like you are on the right track anyway.

1) On the end of the lock cylinder there is a round notched piece that engages with a drive lug on the ignition switch. It's common for that notch to break on the lock cylinder, and cause problems by not switching the ignition switch fully into the chosen position. It's easy to see when you remove the lock cylinder.

2) It's also common for the blower motor circuit to burn out of the ignition switch from the high current the blower motor requires. This damage is usually visable at the ignition switch connection where the circuit in question will melt the connector and the terminal. A new connector will be required, as well as the switch. The motor should also be checked for excessive current draw.
Good luck, hope it's pretty obvious as soon as you take it apart.

BearKiller

When you get home, were it me, I would eliminate the blower circuit from the ignition-switch and control it with a big toggle-switch all it's own; the new ignition-switch will live longer and the truck be much less likely to burn.


Of course, were it me, I wouldn't replace it with a O.E.M.-type unit at all; but, instead, I would over-build and simplify the whole mess with good old toggle-switches and a few well-placed relays, with a plain old-timey dash-mounted switch-key that did nothing other than maybe power up the relays that fed things necessary for the engine to run.

Jim Lane

Here you can take a look inside your ignition switch.

https://www.dieseltruckresource.com/...-t241339.html?

Jim