6.5 odd problem

[ricbob]

I know the quitting part is not odd, but i think the circumstances are. I tryed the search feature and couldn't find anything. Starts right up fine, will sometimes run for a minute sometimes more. When it quits it stops dead not skipping on syntoms. All the gauges on the dash go to '0' If you try to start it, it will not fire. turn the key off for a few seconds and back on,,, the gauges will work and it will start like nothing happened. The colder the temp.. the worse it seems, i have changed the transfer pump. Sometimes in the summer it doesn't quit at all. when i am driving and it quits, i put it in neutral,, shut off the key, if i turn it back on immediately the gauges will stay off.Turn it off for a few and it will start right u and down the road i go, maybe for 10 sec, maybe for 30. Ihave not left the key on,, to see if the dash will come back without turning off the key. It does seem to improve the more i drive it, the duration in between events seem to get farther apart. I believe the other accessories like the heater and wipers etc stay on during this, but can't say for sure now that i think about it. I don't mind spending the money,, i just would rather not "shotgun" it. any ideas would be appreciated. thanks Rick

[a5150nut]

Ignition switch?

A little more detail on the truck would help. Year, model, mods, ect.

[Robyn]

Welcome to TDP

I agree with ign switch as the best spot to start.

What is likely happening is one of the main contacts in the switch is heating up and then breaking contact. The interim cool off allows things to work again for a bit.

There is a lot of current going through the ign switch's several contacts, and these do wear out.

The dash gauges going off is a pretty good indicator for sure.

The ign switch is a linear action switch, and the contacts are copper.
The contact carrier is plastic, and has little springs under each copper contact.
Rotating the key/tumbler unit moves a gear rack that is connected to the switch via a little rod, and this action slides the carrier back and forth in the switch.

As the contacts wear, and over time arc a bit, they build some resistance,
and this causes things to heat up. The heating can get pretty severe at times and this causes the springs to lose there tension.

Once the springs go south. its game over as the contact can no longer maintain.

Had this happen on our 94 Safari van. The digital dash would stop working, and the tranny would not shift.
Along with this, the heater blower and the power windows would quit.

The contact had gotten sooooooooooo hot that it melted the switch and the wire plug that plugged into it. We had to replace the plug. (Excursion to the bone yard with wire cutters)

Missy

[a5150nut]

And if your loking for the ignition switch, it is a small box on the lower end of the steering colum. :D

And welcome to TDP!;)

[DennisG01]

I had one go bad, but the ECM would go into "security" mode and it wouldn't restart for about 12 minutes. But, I think the security light would illuminate - maybe it was different in my case?