i crossed a wire on my trailer harness and now truck is at 7volts

[youngbuckwithapickuptruck]

*edit* no short, i just just playing with lights and not driving a few days in a row and battery voltage went too low ...and of course the voltage will drop when the headlights are on, duh
-thnx for the help!

*original post*
i had my headlights on and i was cleaning my 4pin trailer light wire harness with a wire brush and crossed the ground to running lights and saw a little spark. now my trucks voltage at the battery sits at 7volts. but when i switch the headlights off, the battery voltage jumps back to 12volts.

i visually examined all my fuses in the cab and under the hood and they all look fine, what is the next step for troubleshooting?

do i need to be weary of starting my truck up with head lights off and then switching the headlights on while truck is running?

 

[RobbieD]

It might just be that your battery has a low charge. Start the truck and let it run to charge the battery. While it's running then test all of the light systems, head, parking, turn, backup, for proper operation. I can think of no reason to be wary of from turning on the headlights while the truck is running.

 

[Uncle Gump]

One would think the park lamp fuse would have blown. Do the park lamps still work?

I agree with it sounds like your battery is low... and what you're saying makes no logical sense

 

[youngbuckwithapickuptruck]

update:

i left battery plugged in and headlights on for about 60-90minutes while i asked the internet what happened. in that time it drained the battery down to 7volts. seems like truck was pulling a lot of power in those 90minutes and im worried i may have caused more damage... im gonna pedal the battery to autozone so they can charge it for me

 

[RobbieD]

Don't trust anybody from the Government.

Don't trust anybody over 30.

Don't trust the internet.


You probably just ran the battery down.

Most likely- the wire brush didn't provide enough of an electrical contact to create a dead short, so it didn't blow any fuses.

Headlights are a major current draw- the battery ran down with them on for that long without the engine running.

Get the battery charged, then check your light systems. You're probably worrying about problems that simply aren't there.

Once that's done, if something don't work, THEN we can start troubleshooting.


Take a deep breath; it'll be OK. Good luck!

 

[youngbuckwithapickuptruck]

mods, can we delete this useless thread?

i was testing my trailer lights and not driving the truck the previous two days so the battery mustve gotten pretty drained AND of course when the headlights are on, the voltage will drop

...and if the thread doesnt get deleted, two questions:
does plumber grease work in lieu of dielectric grease.
also if all the ends of the harness and all the trailer wires seem to be pulling 12v then any issues i have should be with the ground, ya? brake lightss stay on but turn off when i apply the brakes.
i already cleaned the grounds on all lights once but i guess now i need to wire wheel every nut and bolt and apply dielectric grease as well, ya?

 

[RobbieD]

does plumber grease work in lieu of dielectric grease.

I wouldn't try it. "Dielectric" grease is non-conductive; you make a clean connection then put dielectric grease over it to seal and protect it. I really recommend that you get the right stuff.

but i guess now i need to wire wheel every nut and bolt and apply dielectric grease as well, ya?

Yes, it's very important to clean up the grounds, but there's other concerns as well on an older electrical system.

Wire terminal contacts inside of harness connectors also corrode over time. These include the harness's inline connectors Carefully disconnect the connectors and inspect for corrosion (green crud). Spray contact cleaner is your friend here. Old plastic harness connectors will be brittle- be gentle with them. In some cases the metal terminals themselves will weaken with time, and need to be carefully bent back into place a little bit, to make better contact.

Terminations within the harness can rot, too. This is where the copper wire strands are crimped into the metal terminal. You're looking to correct any discoloration, green crud, broken wire strands or loose terminations. Repair usually is to re-terminate the connection with a correct new terminal. Grounding ring terminals commonly have this kind of failure, from being exposed to air and moisture.

On the wires within the harness, any damage or open spots on the plastic insulation will commonly have the green crud rot on the copper strands on the inside, where you can't see it. Any damaged wires or their insulation should be inspected and addressed.

It's always a good idea to disconnect the battery when you're dicking with the harnesses. Just disconnect the battery negative cable. Smokey the Bear will greatly appreciate it ("Only YOU can prevent truck fires.").

One last thing here- do you have a wiring diagram for your truck? If not, get one. It'll be worth every penny that you paid for it.