truck turns over without keys

[Jimco]

Good info to know. You mentioned there is 12 volts coming from the fuse box to the starter relay could water be jumping power to that wire constantly causing the starter to run? Also I'm getting continuity between the frame and the power harness to the battery.. doesn't that mean that all the grounds are now charged with power causing the stater relay to feed the starter?

[klhansen]

Originally Posted by Jimco

Good info to know. You mentioned there is 12 volts coming from the fuse box to the starter relay could water be jumping power to that wire constantly causing the starter to run?

Probably not likely. Water isn't really that good a conductor even if it could bridge to that wire. The ignition switch is the first normally open switch in the circuit, then the Tranny or clutch switch. That switch will be closed in the case of the automatic tranny and open on the manual tranny trucks unless the clutch is fully depressed. A short between a normally hot wire and the trigger wire to the relay would do it, but that's not a real common occurrence. I don't even think there are many normally hot wires running with the starter relay circuit after it leaves the last switch in the circuit.

Originally Posted by Jimco

Also I'm getting continuity between the frame and the power harness to the battery.. doesn't that mean that all the grounds are now charged with power causing the stater relay to feed the starter?

No, if there was truly continuity between the battery positive and the frame, you'd be seeing smoke coming off the insulation, or a fusible link blowing out. If by continuity, you're saying you're measuring 12V between the cable and the frame, that would be normal. If somehow the frame was at 12 V, then your voltemeter would measure zero and the starter wouldn't run at all, because there would be no voltage across it (12V from the battery and 12V at the frame ground equals zero volts).

I think the most likely scenario is the switch inside the starter solenoid has broken and the contacts are lightly together, enough to pass current thru them intermittently.

Try the troubleshooting disconnections I mentioned in my earlier post above and see what happens.

[Jimco]

Originally Posted by klhansen

Probably not likely. Water isn't really that good a conductor even if it could bridge to that wire. The ignition switch is the first normally open switch in the circuit, then the Tranny or clutch switch. That switch will be closed in the case of the automatic tranny and open on the manual tranny trucks unless the clutch is fully depressed. A short between a normally hot wire and the trigger wire to the relay would do it, but that's not a real common occurrence. I don't even think there are many normally hot wires running with the starter relay circuit after it leaves the last switch in the circuit.


No, if there was truly continuity between the battery positive and the frame, you'd be seeing smoke coming off the insulation, or a fusible link blowing out. If by continuity, you're saying you're measuring 12V between the cable and the frame, that would be normal. If somehow the frame was at 12 V, then your voltemeter would measure zero and the starter wouldn't run at all, because there would be no voltage across it (12V from the battery and 12V at the frame ground equals zero volts).

I think the most likely scenario is the switch inside the starter solenoid has broken and the contacts are lightly together, enough to pass current thru them intermittently.

Try the troubleshooting disconnections I mentioned in my earlier post above and see what happens.

thanks again for the info. I just got my haynes book today I went over the schematics for the starter and it makes more sense now that I can see how its run. Ill try going through the steps you mentioned.

Also sorry about the continuity confusion, I'm looking so hard for the culprit that common sense tends to leave me sometimes and I forget that auto electric is a little different than residential :P

[bigb]

Originally Posted by Jimco

thanks again for the info. I just got my haynes book today I went over the schematics for the starter and it makes more sense now that I can see how its run. Ill try going through the steps you mentioned.

Also sorry about the continuity confusion, I'm looking so hard for the culprit that common sense tends to leave me sometimes and I forget that auto electric is a little different than residential :P

Not a whole lot different. You are seeing continuity because your meter is looking thru loads, like light bulbs and motors. Those loads have resistance, which is why it is not a short circuit (with smoke) but it is continuity. If you switch your meter to Ohms you will see some resistance. If it was a dead short you would see no resistance, or very little (and smoke).

You will find continuity between the hot and neutral in your house too, when things are plugged in on the circuit.

[Jimco]

Originally Posted by bigb

Not a whole lot different. You are seeing continuity because your meter is looking thru loads, like light bulbs and motors. Those loads have resistance, which is why it is not a short circuit (with smoke) but it is continuity. If you switch your meter to Ohms you will see some resistance. If it was a dead short you would see no resistance, or very little (and smoke).

You will find continuity between the hot and neutral in your house too, when things are plugged in on the circuit.

I was referring more toward a short leading to ground in residential but your right they are very similar

[h2ologd]

I had this happen to my truck. Turns out my windshield was leaking and water would drip down into the fuse box. This also caused other electrical issues before I discovered the problem.

[2fastc]

It was raining the day it happened here also and the floor was wet. after letting it dry for a day it seem to be back to normal except for the dom light relay clicks extremely fast.