New problem

[bob8619]

This will probably get moved to electrical, I'm posting here because not many people frequent the electrical area so I figured I'll get more responses here.

72 c10 350


Suddenly tonight the truck started running rough and I could tell there was a power problem because when I had the blinker on my tach was ticking with the blinker. I got home and put a volt meter to the battery and 14.3volts while running. I then put it in gear and it drops to about 14.1 and as soon as I turn on the lights, it'll drop to low to mid 13s. SOmetimes it'll sit there idling rough other times it'll stall. After many attempts trying it with different things on or off, it seems to ONLY happen when the actual head lights are on, and in gear.


Any starting points?

[WIDESIDE72]

Check all of your ground connections for corrosion.

[bob8619]

Will do. Will report back with my findings. Also radio stopped working today in case that helps anyones with other ideas

[bob8619]

Checked all the grounds under the hood and no luck yet. I don't know if this helps but if I unplug both head lamps the problem doesn't occur.

[litew8]

Try disconnecting the hot wire to the radio. Sounds like something is shorting out and fried your radio or a fuse.

[VetteVet]

Make sure you clean the ground where the headlight wire attaches to the radiator core support and where the ground from the battery negative attaches on the passenger side to the core support.

Also check the wires on the key switch for looseness and burnt connections.

your voltage readings are not out of tolerance but you must have a lot of resistance through the headlights. Check the wires on the dimmer switch as well.

[bob8619]

I've cleaned all the grounds and it still happens, it isn't doing it every time anymore though. If I do it over and over again . You say there should be a wire from the passenger side radiator support to battery negative? Mine doesnt have that but I'll run one.

It isn't stalling anymore either so now I'm not sure if it was related or if I was experiencing some other problem and thought they were connected.



So to summarize: I have cleaned all the grounds that I have found so far and the power to radio is removed. If I unplug either of the head lights individually , or both at same time, the drop in voltage does not occur. Voltage at battery before doing anything is 14.2 - 14.4 volts and when it does act up it will usually go 13.1-13.6 range.

[WIDESIDE72]

You may have a bad headlight switch or dimmer switch.

[bob8619]

I took the switch out and jumped the wires to get the headlights on and it still happened so I guess the switch is good. I guess as long as it doesn't start stalling again I will just let it be.

[litew8]

Check your wires to see if any are exposed shorting out somewhere.