Electrical Woes

[blazinjimmy]

I'll explain my best...........Truck wont turn over. I put a new battery, replaced starter & selenoid. Started right up, but now 2 days later wont turn over again.
K, now if i only hook up the +, and touch my test light to the Neg post, and any metal part of truck....it comes on, but when I also have the neg post hooked up, it goes out. I'm crappy at electrical...can someone please explain...diagnose my prob?

Thanx

 

[diesel4me]

..

All you did was complete the ground circuit!..if the positive cable is connected,and the negative dissconnected,bridging the gap between the negative and ground with the test light will complete the ground curcuit,and light the bulb..(this could indicate a "draw" on the battery though)--.

If everything is "off" in the truck,and all the doors are shut,no "juice" should be flowing from the battery to anything..(OK,maybe the clock,IF you have one,might still be "on").

....so ,by putting the test light between the positive battery TERMINAL,and the other end of it to the positive CABLE,the light should stay OFF if everything is "normal"..if it lights up something is draining the battery-a bulb is lit somewhere,a wire is pinched and shorted,etc---pulling out fuses or disconnecting suspect wires you think might be shorting out will put the light out when the offending device or wire is located..

If pulling fuses or dissconecting suspect wires doesn't put the light out,it could be the alternator causing the light to come on..

Blown diodes in the altenator can cause the test light to come on--the big red wire on the back of the alternator will have to be removed from the stud to see if the light goes out,because that wire is "hot" all the time,even with the key off..(so don't let it touch ground while it's off,or ZAPPP!!)..

I see lots of trucks with stoplight switches that dont release and turn the brake lights off,or with butchered trailer wiring added to the original harness that has shorts, and kills the battery eventually..usually the battery or altenator get the blame,but it's not their fault most of the time..usually its faulty wiring, or something not shutting off,like a trunk or glove box light,or an underhood light,etc..

 

[TBlaz8]

it might be your fuses, check the one for the spark plugs and starter, there under the driver side dash.

 

[W7NB]

Check the battery voltage...

First thing I would check is the battery voltage. Put the appropriate leads of your multi-meter on the battery terminals and see what the voltage is - should be 12 volts + (Usually somewhere around 12.80) If it's below 12 volts somthing is draining your battery and will need to be traced down.

If it's above 12 volts turn on the headlights and check it again. If the lights are dim and the voltage still is above 12 volts you have a loose connection or bad cable - check both the negative connection from the battery to the frame and the positive side to the starter. More thing to check after, but try these first.