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K5 won't shut off with key

wheels87k5

wheels87k5

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A new mystery happened today. I got all my gauges working.....that's a good thing. Started it up and it ran great. Good oil pressure. Water temp climbed as it should. But battery was only showing about 10.5 volts. Checked it at the battery posts and only about 10.5 volts. Went to shut it off and nope. Turned the key off and truck kept running. Had to pull pump connection at the relay. Then it struggled to restart after plugging pump back onto relay. Like it was hot or low battery. And battery only registered 10.5 volts.

What gives?
 
Could be a lot of things. 1 at with key off, see if any fuses are hot.
 
It shut off fine before I worked on the gauges. It still wouldn't restart like it was a hot starter but I checked the temp and the starter was about 125 degrees. At the time I didn't check battery voltage.

Got all the gauges hooked up and this happened. As far as alternator wiring backwards, there is the plug for the alternator and the hot from battery to post on back of alternator.

Wes Harden said:
Could be a lot of things. 1 at with key off, see if any fuses are hot.
Click to expand...

Can you elaborate a little more on this?
 
Any other new gauges installed? Just wondering if a volt meter to could be wired to somehow do this.
 
nvrenuf said:
Any other new gauges installed? Just wondering if a volt meter to could be wired to somehow do this.
Click to expand...

No new gauges. Using all the ones when I had the 350 TBI. All Autometer.

I'm going to start with disconnecting one gauge at a time to see if wiring to one of them is causing this. I'll start with the volt meter and go from there.
 
Yes start there. Wonder is something is wired in a fashion creating a latching circuit
 
Just checked battery and it's only got 4.2 volts so something definitely is drawing it down. And the search continues.
 
If you are measuring 4.2 volts actually at the battery with a voltmeter, not the dash gauge, you have a dead and/or bad battery. To draw a fully charged battery down that low would probably boil the electrolyte in the battery, and would require a solid copper busbar capable of handling 700-1000 amps of current.
There is nothing in your vehicle that could draw a charged battery down that low.
If its at the dash gauge, then you probably have a bad connection in the system somewhere. But you need to double check the actual battery voltage at the battery first just in case.
 
Would a bad alternator drain a battery? Yesterday, while the truck was running, I was only getting 10.5 volts at the battery and at the back of the alternator.
 
Well it wouldn’t charge, so you’d only have battery voltage
 
And 10.5 is a very weak/dead battery. You need to try charging the battery before you do much else. If a diode was shorted in the alternator, it could kill the battery and not charge it either. But that is fairly unusual. Take one of the battery connections off, and put on a charger. We need to see if that battery will hold a charge before we start looking for shorts.

This chart is fairly close.

car_battery_voltage_chart_3-1024x576.jpg
 
Fordum said:
If you are measuring 4.2 volts actually at the battery with a voltmeter, not the dash gauge, you have a dead and/or bad battery. To draw a fully charged battery down that low would probably boil the electrolyte in the battery, and would require a solid copper busbar capable of handling 700-1000 amps of current.
There is nothing in your vehicle that could draw a charged battery down that low.
If its at the dash gauge, then you probably have a bad connection in the system somewhere. But you need to double check the actual battery voltage at the battery first just in case.
Click to expand...

Bad battery. Tried to charge it here at home and after 10 minutes it kicked off the charger. Took it to Oreillys and their machine asked if it was a 6 volt battery. So I bought another battery and go from there.
 
I unplugged all the gauges and truck will not shut off with the key. So I removed the gauge fuse and it shuts off. Uh Oh. It didn't do this the other day so not sure what to look for.
 
So some where the guage fuse is getting power on the wrong side. See if there is power on both terminals w/o fuse in place. This is back feeding other circuits, the one for ignition.
 
With key off.....no power to either side of fuse when pulled. With key on.....power on right side of fuse.

I also notice that the starter stays engaged for about 3 seconds after starts.
 
Is there any chance that the ignition itself is bad? I have traced back any and all wiring I have done. Nothing looks out of the ordinary. I even disconnected wires to see if one would be the culprit but nada. This just suddenly started happening. Before I worked on the dash gauges the truck would fire up and shut off with no issue. I changed or added nothing.

How do you test the ignition to see if that could be the trouble?
 
It is possible, is why I want you to check to which fuses had power with key off
 
Sorry for the confusion. I read it as you only wanted me to check the "Gauge" fuse only. I'll check the rest. Thanks
 
Checked all fuses with key off and the results are:

Horn/Dim.......right side has 12v
Stop/Hazzard....same
Tail Lamp/Courtesy....same
ECM B.....same
Power/Acc....same

All other fuses had nothing
 
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