Pete 378 key switch problem, HELP!!!

I would check the connections around the starter, the power to the dash should go through a breaker mounted to the frame near the starter.

 

Check in the battery box and see if there is a big 30 amp fuse in there or a braker.

 

Sounds like the key switch itself or the ignition power wire from the key switch. Most makes have a main power wire to the key switch, then depending on how you have it turned switches the power to that system. Since acc is working, the key switch is getting power, so the batteries, starter connections should be good. Chances are the ignition wire from the key switch may have a burnt or loose terminal at the back of the key switch, or the wire will trigger one or more relays to continue power to all the ign powered circuits. Look for any relays or breakers/fuses named or called "ign", "ignition power" or something like that. Make sure they are in working order.

 

There is a circut breaker for the ignition on a Pete inside where the fuses are that is below the level of the little door you take off to check the fuses. You can't easily see it because it is down low. Its under the other circut breakers you see. Make sure it didn't pop out, if it did, you will be dead in the water like you described.

 

I was opposed to start a new thread as I have this exact same problem in a 1998 378 with C12. The only difference is that the ACC or RUN doesn't appear to have power.

I was under the dash prior to this problem the other day, trying to figure out why my tachometer intermittenly doesn't work.

I checked the circuit breaker labeled "IGN" in the fuse panel, it is not poped. I checked the ACC fuses as well, all fine.

I cleaned the posts and checked the batteries, all are fine.

I looked for additional circuit breakers near the starter, have yet to find any.

Is there anymore insight someone can give me to this problem? Does anybody have a wiring diagram for this model of truck? Do you think I may have pulled a connection loose when I was looking for the tachometer issue? I am going to pull the key switch out later today, and make sure it is working, and to see if there is power coming into the switch. Thanks in advance.

 

Just an update.

I checked the key switch with ohm meter, it opens and closes circuits properly. I checked the voltage at the BAT lead on the switch, .8 Volts. I was hoping for 12.5V minimum! Any ideas???

This will be my last used truck...

 

Look inside the frame rail near the front of the starter. May need a mirror to even see the breaker. Look for green "stuff" around the connections, should be 3/8" nuts fastening the terminals to the breaker. These get corroded & you are dead in the water. Jus' tryin'

 

There is also a "main relay" mounted right behind the "C" panel of the dash, the small one to the outbuard side of the steering columb. Be worth chesking also. Stil' tyrin'

 

Ok, so I found the breaker by the starter. There are two leads, both hot with 12.6 V. I took the leads off and cleaned them up, still nothing.

Also jumped the solenoid, motor turns over. Will not fire, obviously.

I am lost on the "C" panel. I need a better description. Is this located near the fuse panel?

Last thing, I fiddled with the circuit breaker labeled "IGN". The white push button popped out 1/4". Now it won't stay in. There is no resistance either, it just pushes in and springs back out. No clicks or anything. Possibly a faulty breaker?

Thanks for the reply!