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Hello everyone. I write this post from my shop desk, shop being the high school shop I am now teaching at. I am having a heck of a time trying to figure out my W200's issue. It is a 1970 W200. I drove it from home to the hardware store, and then to the school. I shoveled out the snow so I could bring it inside. I started it up, turned on my headlights, and they went on then it dimmed as soon as I put it in gear and now I am having no electrical. No headlights, nothing coming alive when I turn on the ignition, nothing at all not even brake lights.

The battery is good, and if I jump the solenoid it will turn over, but nothing comes from it. I have unbolted the ground from the engine block, and cleaned it with a wire brush, both the mounting point and the terminal. I have no corrosion on the posts. The connections are tight at the posts.

Anyone have this happen to them as well? I have had it happen a few times now and normally jumping the solenoid fixes it, but not this time. I would really like to get it into the shop so I can replace the driver's window and get ready for my intake swap.

Please advise if you can.

I would check your firewall connections and grounds. Fuse block as well

How many ground connections are there at the firewall?

Any idea?

Should just be a jumper from block and there is one near headlights

Do the 70's trucks have a fusible link that powers everything except the starter? If so it might have blown.

WAWII wrote:Do the 70's trucks have a fusible link that powers everything except the starter? If so it might have blown.

I believe they do. Something to check on for sure.
Also, I'd pull the firewall bulkhead connectors and inspect them.
Perhaps throw a little dielectric grease on them as well. As
always..... check all of your engine/body/frame grounds too.
John

Sounds like it could be an ammeter failure to me. Bypassing it is quick and easy to do to eliminate it as a probable cause.

Methinks is it is time to get out the voltmeter and start seeing where you DO - and where you DON'T - get power to.

Key off, you should get power past the starter relay (had a newer aftermarket one die on me last year),
1) to the Alternator (big post), and
2) to half of the fuse panel under dash (left half, IIRC?).

See topics 6 and 9 of my other post about the bulkhead connectors and ammeter wiring if you get to #1 but not #2:
viewtopic.php?f=21&t=34977&start=20

Let us know where you are able to get the full battery voltage, or real close (12.6 volts DC, fully charged and resting battery).

- Walt

After doing some very scientific testing (jiggling wires with the headlights in the on position) i believe I narrowed it down to the black wire coming off the top of my alt. I jiggles this wire and the lights came on , i jiggled it again and the lights went off. Now since this leads into a rats nest of wiring (have to love previous owners right?) I do not know if it is something I am jiggling in the rats nest, or if it is the same wire just make a better connection.

I'm thinking this summer might be a good time to try and get a new wiring harness, and redo it all.

I am having pretty much the exact same issue with the exact same truck. I am also considering a new harness. Did you have any luck locating one?

If you search the boards for wire harness you will find a few different guys that have done it. I did find out that my pickup is working with a ground being held at the firewall by about 5 strands of copper wire. That is what my problem is.

If I decide to keep the pickup I will get a new harness and run it, but If I sell it I will not be doing that work. Hope this helps.

Interesting you mention the body ground. I work with a guy who restored mopar cars on the side. He also mentioned I should check all of the grounds, not just the battery to engine ground. I will have to check this out when I get a chance. He suggested a company called M and H Wiring in Santa Fe Springs, CA. I emailed them to see if they can help me out. I emailed Painless wiring but they have nothing to offer.

I spent a few minutes looking around, under, inside...and cannot find the body ground. I assume it is attached at the firewall somewhere. Anybody have information on where it is?

There should be a flat braded wire to the cab from rear of engine, (either off the head or manifold). Also should be a flat braded wire from rear of cab to bed. Of course the flat braded wire might have been replaced with any type of stranded wire.

Thanks I'll check that out.