Electrical failure....Help

[Davemn]

I turned the key on, everything normal, hit the starter and everything went dark. No cranking, no lights.
Here is what I know........
Voltage at the battery is ~13 volts with the key OFF. Fresh charge.
Voltage goes to zero when I turn the key ON.
No idiot lights or headlight when I turn the key on.
With a 6 amp charger on the battery, headlight and idiot lights work but it won't crank over.
Headlight goes off like it should when I hit the starter.
Fuseable link tests ok.
Do I have a bad starter switch? Did maintenance once a few years ago. Bad battery?
Thanks
98 with 51,000 miles

[Hook#3287]

Sounds like starter switch.

You could try jumping the starter relay, that will tell you starter's good.

[Itinifni]

When you say "voltage at the battery is 13V with key off...voltage goes to zero when I turn the key on" how are you measuring that, please be specific.
If you are measuring your voltage directly at the battery posts with a multi meter (as opposed to on the cables or with a hard wired voltmeter) go no further, you have a bad battery.
If the battery is in fact bad with an internal short or open under load your 6 amp charger is not enough by itself to crank the engine.

If you're checking your voltage elsewhere as with a hard wired voltmeter or at the fusible link you may still have a bad battery but it's more likely a bad connection.
You can chase it with a volt meter.
1. Place both the positive and negative cables of your meter directly on the corresponding posts on the battery. Key off, key on, crank. If your voltage drops to 0 or near 0 under any of these conditions your battery is bad. If voltage remains the same as key off or close to it move on.
2. Place both meter cables on the cable lugs on top of the battery and repeat Key positions.
If voltage drops to 0 or near 0 under any key position you have a bad connection at the battery. If it remains the same as key off move on.
3. Place the ground cable of your meter back on the negative post of the battery and move the positive cable to the fusible link and repeat.

You can follow the power supply all the way down the circuit this way if you wish checking each side of each connection like you did with the battery, I hope that makes sense.

One connection that could easily be missed is the other end of the negative battery cable which can be seen by looking above the left side driver's foot peg and bolted to the back of the transmission.
Easy to check but a little counter-intuitive the way I will explain it.
Place the negative cable of you meter on the negative battery post, place the positive cable of your meter on the engine block or better yet one of the bolts in the back of the trans near the negative cable. You want a clean connection. This time when the key is on or cranking if you see 0.5 volts or less the connection is ok, if you see 12V you have a bad ground circuit back to the battery.

Of course the easiest thing to do first is to remove and clean the battery connections.

Don't hesitated to ask for clarification, I know I can go a little overboard sometimes.

Good luck,
Matt

[/list]

[Harryc]

Simple...remove the battery, take it to the nearest auto parts store and get it load tested.

[Davemn]

Digital volt meter at the battery posts.
Battery posts clean and tight.

[frankn101]

Simple...remove the battery, take it to the nearest auto parts store and get it load tested.

 

It is probably the battery. Shows full voltage but upon load has no current capacity. That's the obvious first thing to check. load test it.

[Itinifni]

If you're right on the posts with 13V static and 0V dynamic it's the battery. No harm in having it tested if you have a place that will do it.

Easy fix if not cheap.

Matt

[Hook#3287]

Man, getting old.

I totally missed this part

Voltage goes to zero when I turn the key ON.
No idiot lights or headlight when I turn the key on.

[Davemn]

Thanks Gentleman. 2 year old AGM battery from Wally World. Not sure I will go that route again. I know the material in the cells are thinner in a glass mat battery.