Headlights flickering - Location of hood harness ground?

[Hum]

Headlights occasionally turn off when going over bumps. Both headlights simultaneously. Dash lights not affected. Alternator voltage not changing. Where does the chassis harness to which the hood harness connects to get a ground?

 

[NormB]

You'd have to find the wiring schematic and do a circuit trace to figure this out, maybe.

The hood, being fiberglass, connected to the frame via two greased hinges, isn't grounded. (file under "DUH!").

So where's the ground wire(s)?

Follow the hood wiring harness to the Cannon plug on the left hand side. With your handy-dandy Volt-ohm meter (and aforementioned wiring schematic) you can do continuity checks and bang around to see if the circuit is interrupted. This will help localize the "break" or bad connection.

You could also look at the numbered aluminum tabs on the headlight wires and I THINK there are similar tabs by the cannon plug. Each headlight has one wire for high, one for low, one for ground. I suspect the grounds are connected somewhere before the cannon plug.

Also, clean the plug connectors and put on some DEOXIT. Do this to any and every connection you can find. You'll thank me.

Now, if you CAN'T get the lights to flicker (or "PEEP" from your handy-dandy VOM to stop) while doing this, the problem is closer to the cab, possibly from the dash light switch.

Repeat the above cleaning instructions with the cannon plug there, and on the turn signal AND FOOTSWITCH (High/Low beam) while you're at it.

DO DISCONNECT BATTERY GROUND BEFORE DOING ANY OF THE ABOVE.

Beyond that, you're looking at one or several of the packard connections gone bad somewhere and you'll need to circuit trace the headlights, break each connection, clean/replace/deoxit and reconnect.

Hope this helps.

But you wanted a hobby, right?
Norm

 

[Bulldogger]

Each headlight has its own ground wire, should have a metal tag labeled "91". Since they BOTH flicker, in that case I'd check the light control panel connection, though that is a screwed in connector, so shouldn't be a problem.

It occurs to me, that on my HMMWV I noticed that if I turned the lever all the way to the right, the normal "all lights on" position (Service Drive is the label), sometimes my headlights would cut in and out. I discovered that if I turned the lever all the way right, released the Unlock lever, and THEn turned back left a tiny bit, my headlights don't flicker anymore.

I suppose this means my light switch needs replaced or cleaned, but I've read horror stories of all the springs and innards flying out of these when opened, so I just fiddle with the lever and I'm happy. (That came out wrong, but oh well.)

Try that first, it's the cheapest fix!

Bulldogger