Several cut factory wires under hood. Help I.D. trace repairs...

[jacqueskruseo]

Hey folks, I've got a few things I'm asking for some help with. I noticed a few cut wires in the factory wiring harness under my hood the other day. I've looked over the very helpful threads from MrMopar, and I've traced down what I could but I'm still blank on these issues. Here's a few pictures of what I noticed was cut under the hood.

Info: 1970 D200 Camper Special regular cab. 318/3speed auto

First, I have a cut "RED" wire in a wiring harness. This harness is the set of wires running from the connection block located next to the brake booster on the firewall. The wiring then runs down the driver side fender, and the other "cut" end protrudes out of the wire wrapping. These are the 2 photos below. This wiring harness continues on to the front lights of the truck, running just up to the driver side of the radiator. I do not see any cut connections anywhere else on the block connectors on the firewall that this may have been part of.





Next, there is a "BLACK" wire cut which is part of the ballast resistor wiring harness. After tracking down this section, I have found the other end of this wire is running to the alternator, but it is simply twisted around a long threaded fastener on the top side of the alternator. There is also a larger gauge "Black" wire running off the ALT, but this wire runs directly through the firewall and I have traced it to the back side of the dash cluster. This is not what is shown in MrMopar's wiring images, so maybe there is some variations to the production dates and/or it's just changes unknown in the records.



The last thing I could do is really look over all 3 of the block connectors on the firewall, checking them against the wiring diagrams. To note, I do not have any issues that I've noticed so far. That is, all my lights work, and the relay I've added under the hood is all new for my fog lamps.

As a quick reference, here are the links to the wiring diagrams that have been really helpful!
viewtopic.php?t=27800

[swptln]

Not a 100% sure, but those look like they might be your amp gauge wires. Those diagrams in that link you posted are not factory diagrams, thus why they're wrong or have mistakes. Those are some aftermarket diagrams, from a Chiltons, Motors or Haynes manual. The FSM has a lot more detail and they are correct.

[jacqueskruseo]

Thanks Mark. I didn't know those other images were something aftermarket like Chiltons. Would you know if anyone has posted images of a FSM online somewhere? Or has anyone uploaded them to another website?

Justin

[swptln]

PM Sent

[johnah]

Those wires may be left over from an AMP gauge by-pass. Lookup Dodge gauge bypass MAD Electrical. Even if that's not what your looking at you'll find some good info on that web site.
Until then swept on, john

[Hobcobble]

http://www.sweptline.com/tech/70wire.jpg

John

[swptln]

http://www.sweptline.com/tech/70wire.jpg

John

John, that is the same exact diagram from mrmopar (I think he just copied them from sweptline.com)and they are incorrect diagrams. Those are some rendition of the original and half the info from the FSM diagrams are missing. Termination identification, wire size, wire name are missing and the wiper switch, headlight switch, directional switch, starter relay, hazard switch, among others don't even have the correct configuration for the wiring. I've seen those diagrams before and not to be negative, but they suck.

[Hobcobble]

John, that is the same exact diagram from mrmopar (I think he just copied them from sweptline.com)and they are incorrect diagrams. Those are some rendition of the original and half the info from the FSM diagrams are missing. Termination identification, wire size, wire name are missing and the wiper switch, headlight switch, directional switch, starter relay, hazard switch, among others don't even have the correct configuration for the wiring. I've seen those diagrams before and not to be negative, but they suck.

Good to know Mark. I figured they were direct copies out of the corresponding
model year FSM. I'll have to see if I have a FSM newer than '69 so I can take a
look at the diagram....

John

[swptln]

This is a 1969 FSM wiring diagram. If you look, you'll see there is no comparison to the one's on sweptline.com.

[Wildergarten]

I noticed a few cut wires in the factory wiring harness under my hood the other day. I've looked over the very helpful threads from MrMopar, and I've traced down what I could but I'm still blank on these issues.

It was pretty common for the spade lugs on the alternator lines in and out of the dash to fry inside the bulkhead connector block, short to something, and then fry the wire (spade lugs are way too resistive for that much current). A pretty common fix was to run wires directly off the alternator through a drilled hole in the firewall to the ammeter and back to the starter relay. Most rarely used a decent grommet, and even if they did, they don't last long. So chances are that the mechanical protection for the wire insulation where it goes through the sheetmetal is inadequate. I plan to put a couple of 5/16" stud bulkhead connectors through the firewall for those high current lines.

[swptln]

I noticed a few cut wires in the factory wiring harness under my hood the other day. I've looked over the very helpful threads from MrMopar, and I've traced down what I could but I'm still blank on these issues.

It was pretty common for the spade lugs on the alternator lines in and out of the dash to fry inside the bulkhead connector block, short to something, and then fry the wire (spade lugs are way too resistive for that much current). A pretty common fix was to run wires directly off the alternator through a drilled hole in the firewall to the ammeter and back to the starter relay. Most rarely used a decent grommet, and even if they did, they don't last long. So chances are that the mechanical protection for the wire insulation where it goes through the sheetmetal is inadequate. I plan to put a couple of 5/16" stud bulkhead connectors through the firewall for those high current lines.

The problem is not the spade connector, it's the wire itself. You have a system capable of putting out 37-60 amps and Dodge only used a 12AWG wire for the ammeter that only has TW insulation good for 20 amps continuously. Those spade connectors are good for 30 amps continuous.........the system is designed to handle the full load for only a short period of time and if everything is working properly the amperage is supposed to decrease in a short period of time.
Then you have the vehicle owner or aftermarket installer factor that adds all kinds of auxiliary equipment on the load side of the ammeter circuit instead of installing a secondary circuit from the battery to handle the load properly. This is why they manufacture relays, but nobody want's to use them, until they start burning up wires and terminations.
The best thing you could do for a normal system on our trucks is to upgrade that 12AWG wire to a 10AWG with a higher class temperature insulation to handle more of a load for a short period of time. Automotive wiring has the lowest class temperature rating of all insulations (TW) for wiring, it's just a low smoke class of insulation.

[Wildergarten]

Then you have the vehicle owner or aftermarket installer factor that adds all kinds of auxiliary equipment on the load side of the ammeter circuit

Oh I think the problems started LONG before that, with the first time somebody left the headlights on and got a jump. It's a major design deficiency. Below is the connector from my '69 W200. The wire was fine. The connector block can't get rid of heat efficiently. Wish I could get a newer one as they work great for all but the two high current lines.

[earlymopar]

[
The problem is not the spade connector, it's the wire itself. You have a system capable of putting out 37-60 amps and Dodge only used a 12AWG wire for the ammeter that only has TW insulation good for 20 amps continuously. Those spade connectors are good for 30 amps continuous.........the system is designed to handle the full load for only a short period of time and if everything is working properly the amperage is supposed to decrease in a short period of time.
Then you have the vehicle owner or aftermarket installer factor that adds all kinds of auxiliary equipment on the load side of the ammeter circuit instead of installing a secondary circuit from the battery to handle the load properly. This is why they manufacture relays, but nobody want's to use them, until they start burning up wires and terminations.
The best thing you could do for a normal system on our trucks is to upgrade that 12AWG wire to a 10AWG with a higher class temperature insulation to handle more of a load for a short period of time. Automotive wiring has the lowest class temperature rating of all insulations (TW) for wiring, it's just a low smoke class of insulation.
[/quote]

Mark: You are correct with your comments on increasing wire size. I used a slightly different approach and left the OEM circuit in place and ran a parallel circuit to the OEM circuit.

- EM

[swptln]

That will help reduce the load on the wire for sure, by dividing it across two conductors........the average person doesn't understand electrical systems. Being in the electrical industry for over 38 years, I've seen some pretty interesting things..especially in vehicles. Electrical connections/terminations are the weakest link in any system and back in the early years they didn't use dielectric grease on terminations for vehicles. Thus, any higher current circuits rear there ugly head over time. As mentioned, the wiring for the Ammeter are not designed for long term high current loads, being trucks this wiring is always overloaded. The biggest culprit is trailer wiring......almost nobody isolates the trailer wiring from the truck wiring. In all my years of wiring trucks and trailers I've only seen one truck other than mine, where they isolated the trailer from the truck wiring.

[Wildergarten]

In all my years of wiring trucks and trailers I've only seen one truck other than mine, where they isolated the trailer from the truck wiring.

I can see trailer running lights on a separate switch, but what did you do for stopping lamps and turn signals on the trailer? Relays? I had a big rig truck turn signal switch on my last Power Wagon, so this isn't just a rhetorical question, as I would prefer to use the stock switch. I've purchased LED bulb equivalents to the 1157 to that end, figuring that the reduction in current would be sufficient to keep from frying the contact set.

[swptln]

In all my years of wiring trucks and trailers I've only seen one truck other than mine, where they isolated the trailer from the truck wiring.

I can see trailer running lights on a separate switch, but what did you do for stopping lamps and turn signals on the trailer? Relays? I had a big rig truck turn signal switch on my last Power Wagon, so this isn't just a rhetorical question, as I would prefer to use the stock switch. I've purchased LED bulb equivalents to the 1157 to that end, figuring that the reduction in current would be sufficient to keep from frying the contact set.

I run a separate power supply directly from the battery and distribute it through fuses, this isolates any accessories from the truck wiring. Using relays controlled by the truck wiring, so there is no additional load put on the truck wiring, only the load of the relay coils, which is minimal. All your original switches or controls just switch relays. Just as an FYI LED's don't always reduce the load.....there are some LED replacement lamps that draw just as much as incandescent lamps. Most are less, but I have run into some of the replacements that draw almost the same.
Coming directly off the battery with a power supply does not put any load on the truck wiring, only the battery.

This was a major problem with Dodge trucks in the 80's and early 90's, as Dodge in their infinite wisdom decided to run a 18AWG wire from the headlight switch to all the marker lights and if you hooked up a trailer to the rear wiring directly, it would fry the headlight switch and connector, 1-ton dually's were the worst with all the extra marker lights.

[Wildergarten]

Just as an FYI LED's don't always reduce the load.....there are some LED replacement lamps that draw just as much as incandescent lamps.

I'll check that. As this is a flatbed work truck, it will have gobs of lights. So extra relays are already part of the build. Wire won't be a problem because I planned from the get go-to replace ALL of it with upsized THHN, except for pigtails from the factory fixtures and some of the dash wiring. If they were using bullet connectors I will replace them with the Packard style blades. I collected a few multi-pin connector bodies over the years so it shouldn't be too much of a constraint.

I have procured some very nice fuse blocks buss bars and relay bodies from Blue Sea Systems (the marine industry; I learned most of what I know mechanically and electrically restoring antique boats). All have seals or covers. The relays are the Bosch style in a six-pack body with fuses. I may go through the firewall with it. There's a photo of the potential layout on my build page: viewtopic.php?f=34&t=42001&p=303614#p303614

So I was onto fixing the current demand problems on the truck, but wasn't aware that the LED equivalents for the 1157 and the various marker lights pulled that much power. I will be adding a fair number of LED clearance lights. So I will check that. I won't be pulling trailers beyond the splitter, the firewood trailers, and possibly a low-boy equipment trailer, most of which are off-road and don't have lights. As to whether that loads that Cole-Hersee dash headlight switch too much, I'll just have to run the numbers. I was planning to hold to 15A as an upper limit or it will get a relay. Or is that a bit much?

As for the alternator lines and feeds to the buss bars, I'm using 5/16" bulkhead studs, #6 wire, and soldered lugs with doubled heat shrink. On the boats, the heat shrink got silicone, which one only gets to do once on a soldered line.

[swptln]

Sounds like your on the right track...............