Front Turn/Marker Light Housing Ground (1 Viewer)

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Aug 27, 2006
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Annapolis, MD
I'm working through the dreaded electrical gremlins on my '78, one of which is that the front driver side turn and marker lights don't light up. I have power going in to the housing from the two wires in the engine bay (one always 12-ish volts when the light switch is pulled that powers the front and side marker bulbs, and one that alternates 12v/0v for the turn signal bulb). If I manually ground the inside of the housing the lights work like they should. I don't see a ground wire anywhere, so I assume the housing grounds directly to the body somehow. Is that right? I haven't been able to take the housing off the truck to clean it up because the nut is very rusted underneath the fender.

Any suggestions on what to do? I could cut the housing off and get a new one, keep at it with PBblster (maybe add some heat), or just run a new ground wire from the housing to somewhere inside the engine bay.

Suggestions welcome!
 

ceylonfj40nut

Waiting for Barn Time
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Grounds via housing and body. Best to try and. Clean rust off. Or run a separate ground from chassis to housing.
 

Bear

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Sometimes undercoating is on the underside of the fender, and the hollow threaded lamp post doesn't get sufficient ground--really need to remove that nut, clean a bit of the fender, and put a star washer under the nut.

A second ground issue is with the upper section of the metal reflectors within the plastic lamp housing. Its ground is via a small metal tab that "touches" the lower metal reflector. And so this, too, is an area that needs cleaned to get a good ground.
 
Joined
Sep 28, 2015
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Plettenberg Bay, South Africa
Just been through the bad-ground-in-the-frontlight-cluster. Bad!

First thing, I was cheap and did not buy the proper OEM part.

After a week or so the ground went bad. I assumed that as the marker light and indicator started flasjing weakly at the same time.

When I opened up I found that the ground inside the light consisted of the metal reflector touching a long self tapping screw. That was never going to work reliably every vibration would upset the "connection."

IMG_7144.JPG


My harness has 3 leads to the light assmbly. 1 for the indicator, 1 for the marker and a ground. The assembly had 3 wires. I had connected them accordingly and it worked at first.

When I looked at the back of the reflector I found that the 3rd wire was NOT a ground, but a live feed to a globe behind the reflector...
IMG_7143.JPG


indicator side light. NOT ground.

Solution for me there was to join the two indicator leads and add a proper ground wire directly onto the reflector.
IMG_7147.JPG


I had also spent hours trying to get my flasher unit to flash consistently with no success. This little excercise also solved that problem.

The after market cr@p reflectors are so shallow they can only accommodate a 10w indicator globe whereas the OE has a 21w globe. Similarly the globe behind the reflector is 10w OE but only 5w Taiwan. 15w versus 31w. I replaced the 5w with a 10w but could do nothing about the front globe.

Tried it and it seems the additional 5w draw is all that was needed. I got lucky.

IMG_7139.JPG


The difference in quality between the OE and aftermarket products is astounding and the time wasted as a result is a pain.

Hope this helps somebody.

Note on last pic that the OE light has a metal tab with a threaded hole bringing the ground from the body and the reflector is secured firmly to the tab with the screw into the ground tab hole.
 

Bear

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Dagha,

Great explanation. It is tempting to buy the much cheaper aftermarket items, but an analysis like yours shows why most aftermarket stuff is cheaper. From a distance, using photos and not actually touching the parts, they look like a great buy; rarely do the adverts ever show the guts of the product and where they cut corners in the manufacturing.

Yes the original, OEM, parts are over-priced, sometimes hard to find, but as an entire vehicle, the old Land Cruisers have survived a long time using sturdy solidly-built parts and pieces. Keeping things original when possible is probably the best way to continue that long life. But we all have to reach this conclusion in our own way and on our own budgets.
 

thebigredrocker

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@Martian remember it's not just the turns/marker housings that need bare metal contact to their mounting surface. The side apron must have bare metal contact to receive a ground from the drivers fender. The drivers fender should be grounded to the frame. I also think it's good to ground the fender to the cowl. And of course you'll have your negative battery cable attached to the frame.
 
Joined
Sep 28, 2015
Messages
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Location
Plettenberg Bay, South Africa
Throughout my build I have concentrated on rust prevention/avoidance and have avoided where possible making ground connections via the body panels as that would require bare metal contact points, creating vulnerability to rust in those areas. Under fenders have lotsa paint, then lotsa stone chip, then lotsa paint again over that. I modified my harness slightly and added ground wires into the harness grounds so I could ground components directly back to the battery.

ZERO BODY EARTH.
IMG_7149.JPG


I also made sure all my wiring is well sealed to keep dust, mud and water out of the harness and terminals.
IMG_7151.JPG


And every terminal soldered. I know there is disagreement on the solder or no solder front, but I like solder.
 

Coolerman

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Jan 5, 2004
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Paint Lick, KY
A quick tip about grounding to body metal IF you are still at the stage where you can weld stuff to the body metal.

Weld 6mm x 1.0 x 12mm bolts to the sheet metal in locations you need a body ground. Weld the bolt HEAD to the sheet metal. Paint and under coat as desired. Run a 6mm die over the threads to clean them if you didn't mask them off during painting.

When it comes time to ground your light: Place a flat washer over the stud. Put a drop of RED Locktite just above the washer. Put one 6mm nut onto the stud and tighten just enough to be firm but not gouge the paint/undercoating. Put a 6mm ring terminal over the stud followed by a 6mm star washer. Now thread another 6mm nut on the stud and while holding the bottom one to prevent it from turning, tighten the top one. Result? No broken paint/undercoating to allow water in, and a good solid ground. Depending on how long a bolt you use you can use this for multiple grounds just by stacking nuts and ring terminals.
 

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