crazy electrical problems

[cousindave]

I ran outside today and start the series III. She cranks over one time, and then nothing as if the battery died. I grab the battery charger and as soon as I plug it in the needle on the charger hops all over the place and then the breaker on the charger pops. My voltmeter in thee series reads nothing. When I first turned the key the voltmeter read 12v now nothing.I recently(within the last month) replaced the battery, ignition switch and solenoid. I have cleaned off all connections checked all the wires and can not find any thing wrong. Can someone tell me how to check the ignition switch? It,s new but the quality is suspect. It,s an allmakes brand. It's the only thing I can think of. Thanks

[NickDawson]

Sounds like something is grounded that should not be.

I dont know a lot about the switches in the series II trucks but suspect you could test for continuity. I'm assuming there is a hot lead input and two outs - one for accessory position and one for the starter. You might also check and see if the body of the switch is grounding out against the body of the truck? Dunno really...I'm talking outta my rear on this one.

You could also remove the switch and wire the hot lead to the accessory position directly (temporarily) and see if things look normal (with the onboard voltmeter). If it does look normal, its the switch. If not, start checking the fusebox under the steering wheel - I think Im correct that it is downstream of the ignition switch.

[Nium]

Here's my take on places to look. The starter or solenoid is bad allowing for full current to flow from the battery. With a starter short when you connected the battery charger it was basically like connecting the two leads of the battery charger together and turning it on.

Disconnect battery
To verify starter or solenoid problem. Disconnect cable at solenoid that goes to starter.
Reconnect battery
Turn ignition switch to run position.
If all other electrics work (lights, wipers, etc.) starter or solenoid the problem
Using a voltmeter test for voltage to ground at post, on solenoid, of disconnected cable to starter. Should see 0V. If you have someone turn the key to the start position you should see the voltmeter jump to battery voltage and back to 0V when key let go.
- If there is always battery voltage at that post regardless of key position then solenoid not working properly.
- If the solenoid is operating correctly there is something wrong with starter and it should be closely examined for path to ground causing a large short.

Or it's something else :p. Iginition switch operational verification is fairly straight forward using an ohmeter. Disconnect wires from the back of switch and verify continuity between posts at appropriate key positions.

[cousindave]

Thanks guys for the great advice! There is only one problem: I went out this morning to perform these tests reccomended by Nium, and she fired right up. Go figure. I checked the battery and voltage read 13.15. Everything else also checks out fine. Any advice on how to trace an intermittent problem? Thanks again!