'69-'71 Electrical System - component by component

[PwrWgnWalt]

While re-wiring my '70 W200, have uncovered a few odds-n-ends things that are not covered by the Service manual and/or its Wiring Diagrams.
So, thought I'd start this compilation of posts, each one covering a different component of the wiring. Should be good for '70-'71, most '69, and may be of value to other years as well.

First - the Headlight Switch

The headlight switch, whether stock Mopar or aftermarket, is designed to transfer power from two power inputs (B-1 and B-2) to various circuits depending on the position of the switch. The switch can be "Off/fully in"; "Parking/halfway/pulled out one stop"; or "On/fully out". Using a multimeter, here's what I find...

Looking at a couple of wiring harnesses and switches, and working counter-clockwise from the lower left of the pictured switch:

B1 - large Dark Blue (12 ga.) [power IN from the non-fused Alternator wire, the big black one coming in from the bulkhead connector #16.]
This powers only the H circuit when the switch is ON/pulled fully out.

R - Brown (16 ga.) AND Dark Green (18 ga.) wires (in my harnesses), but only Brown in wiring diagram [Brown is the Running Lights circuit. The Dk Grn wire being here allows the parking lights to be ON when the headlights are on, too... see "P" at bottom.]
This gets power from only the B-2 feed, when the switch is either in the Parking/halfway position or in the ON/full out position.

I - Tan (18 ga.) [Instrument Lights, dims on rotation of rheostat in switch]
This also gets power from only the B-2 feed, when the switch is either in the Parking/halfway position or in the ON/full out position.

H - Yellow (16 ga.) {Headlight Circuit, goes to the dimmer switch]
This gets power from only the B-1 feed, when the switch is in the ON/full out position.

D - White (18 ga.) [Dome Light ground; this serves to provide a ground/negative source through the white wire to the double-contact-base dome light bulb, which operates by one contact receiving negative/ground, and the other receiving positive 12VDC power through the yellow wire]
This does not get any power, but is grounded only when the switch is rotated fully counter-clockwise ('click'), flipping a grounding tab below the terminal, behind the ceramic rheostat disc.

B2 - large Red (12 ga.) [Power IN from the Battery, via the Tail, Park and Side-Marker Lights 20amp fuse in fuse panel]
This powers the R, I and P circuits when the switch is in the Parking/halfway position; and only the R and I circuits when ON/pulled fully out.

P - no wire in my harnesses, but Dark Green in wiring diagram - see "R" above [Parking LIght circuit].
This gets power from only the B-2 feed, and only when the switch is in the Parking/halfway position.

[PwrWgnWalt]

Second topic - the Emergency Flasher Switch (Hazard Switch)

The Emergency Flasher switch on the '69-'71 trucks is quite simple... pull it out, and the turn lamps at all four corners of the truck flash in unison.
Unlike earlier trucks, the heavy-duty flasher is attached to the fuse panel (bottom left position), and not to the back of the switch.

There are five terminal posts on the switch *think: the markings/dots of the 'five' on dice. The only key wire in this swtich that must go in a particular spot is the Dark Blue wire - it must go in the center position (16 ga., circuit F38 from flasher on the fuse panel). The other wires (Yellow, Yellow, Lt Green, Dark Green; all 18 ga.) can be placed on any of the 4 outside/corner terminal posts.

As an aside, here are the general color codings for the turning lamp circuits (comes in handy with turn signal switch, etc.):

Right Turn
Front: Light Green
Rear: Dark Green

Left Turn
Front: Yellow/Black tracer
Rear: Yellow

[PwrWgnWalt]

Third topic - Converting to Electronic Ignition (with ECU and modern Voltage Regulator)

I used this to convert my '64 W200 over to the more reliable electronic ignition. Then I used on it on my '70 W200. The modern Voltage Regulator was used from 1970 on up, so is already stock for '70 and later trucks. This diagram is good regardless of which alternator one uses (one or two Field terminals, either is fine. Use what you have!).

One could use just the Voltage Regulator upgrade, without the ECU and distributor upgrade.
Or, if you had a single Field Alternator, and now all you can find is the two-Field version... here's how you wire it in (just ignore the ECU).
However, if upgrading to the ECU, you really must have a modern Electronic Voltage Regulator... (and yes, they do make electronic versions of the old style, if you want to keep your Dodge looking somewhat original... available just about anywhere).

This does require the use of the Electronic Igntion version of the Mopar Distributor (for whichever engine family you have). These are available aftermarket, salvage yard, etc. No more points to change, and retains a stock appearance.

Click for the full view...

[wally426ci]

[crusty]

This is just plain awesome! Thanks for your hard work.

As an aside, I went out to my wiring to place the white wire on the light switch, and per your guidance I looked for the D terminal. Mine has D1 and D2. I assume they are tied together and pick either one? Ever seen that?

[PwrWgnWalt]

Don't know about the D1 and D2 terminals... however, if you have a multimeter, here's how you can figure out what does what:

Set to read Ohms, a low setting is best (I use 200). It should now read "1" with the test leads not touching/conducting with each other - this reading indicates High Resitance/Open Circuit {note - never apply current to the test leads when in Ohm setting - it can/will fry the meter. Ohms only measures the RESISTANCE or continuity of the circuit and is not intended for measuring current or power.]

Touch the test leads together - the reading should be "0" or very close. This indicates "No Resistance/Complete Circuit"

Using the test leads, place the Black/Comm/Ground lead on the B-2 terminal - ensuring good contact. Touch the Red test lead to any of the other terminals to see if they make a "circuit", or not. If the meter shows a low number (in the range of 0.1 - 0.6 Ohms) you have a good circuit and power will feed from B-2 to that terminal when the switch is in real-life use in the position it is in when you made the test (halfway on, or full on) . You will want to try all different terminals, moving the test leads to determine which ones complete a circuit in a given switch configuration.

For the Dome Light function - since it is a Grounding action... Place the Black test lead on the metal case of the headlight switch, then touch the Red test lead to the D (or D-1, D-2) terminals. Remember that the switch knob needs to be rotated to engage the flip-switch, "turning on" the dome light - this is fully counter-clockwise to the 'click' for my switches. I have also seen new aftermarket headlight switches that have a grounded terminal sticking off the back of the switch, probably for a separate grounding wire attach point for plastic dashes - the metal case of your switch is grounded upon installation in your metal dash. It could be your D-1 or D-2 are for this grounding function.

[PwrWgnWalt]

Fourth Topic - Dome Light Wiring (for 1970-1971)

Here is a diagram of the Dome Lamp wiring for those trucks with the plunger switches in the door post (automatically turns the light on when either front door is opened). This Dome Light is also operated by the Headlight switch, by rotating the knob fully counter-clockwise.

CLICK for Full View...

[dodgeboykim]

On my 66 I installed a 69/71 headlight switch and 69/71 dome light assembly to be able to turn on the dome with it. To me a little more convenient that turning around and sliding the switch at the dome light.

[PwrWgnWalt]

Good post, Kim!

That would work fine using the original '66 single-wire (Yellow) power lead for power - just have to run the 'White' Grounding wire up to the new dome light from the new headlight switch. The old-style knob will also fit right into the newer Headlight Switch, so no one can tell (unless they look behind the dash, end even then they probably wouldn't know the difference.)

The old style light only had the Yellow power lead because the Ground (completing the circuit to turn the light ON) was made when the lever on the dome light was flipped - making contact with the cab metal.

[dodgeboykim]

Come to think now I may have used the original dome light assembly and turned to on and removed the handle with the 69/71 lens. I did it back about 25/30 years ago. Its been so so long. Would have to pull it apart to be sure.

[crusty]

Ha! I wondered about that. I lengthened and retrofitted the 2 wire setup into my cab, but I was comparing lengths to the original (1 wire). I wondered how one harness had one and the other had two. Thanks!

[PwrWgnWalt]

Fifth topic - Emisson Control / NOx wiring 1970-1971

While under the hood working on the engine compartment wiring, found an additional wire connector apparatus on the Ballast Resistor, which had a single red wire coming into it from a small additional harness...

This red wire (the Power feed) was attached via this apparatus to the black & red wires coming from the Run side of the Ballast Resistor.
It then went across the firewall to this little gizmo, which I found out is the NOx Spark Retard Sensor.




The wiring then proceeded across the frewall to the right rear of the engine, and connected to this thing, which I found out is the NOx Vacuum Valve Solenoid. The wiring for this thing is tucked behind a large grounding wire, at the upper left of the photo...the red and yellow wires, going to the flat, 2-place terminal connector.



While the vacuum lines in these pictures are long gone, it at least gives an idea of what was orignally on the truck. Apparently this was also present on other Mopars (cars) around the same years. The parts book lists several pieces under NOx Emission Controls, but I could not find any pictures or diagrams for the vacuum hose routing.

Update 12-2-2013: The '70-'71 Service Manual Supplement has details on the NOx system, including wiring diagrams and settings for manual or automatic transmission trucks.

[PwrWgnWalt]

Sixth Topic - Bulkhead Connector & Insulators

So we all know by now that over the years, corrosion on the terminals of the bulkhead connector causes high resistance, overheating, melted wires and plastic, and all sorts of problems. Here's what I've been doing to address this, to ensure another 40+ years of reliable Dodge Truck transportation!

First - these connectors are copper Packard/Delphi 56 Series. Being such, they get that 'patina' on them that is no good for electrical conductivity.
A good cleaning with a steel brush, or replacement with tin-coated versions, plus a good coat of Dieletric grease upon re-connection will help this problem.

Here's a photo of one of my bulkhead connectors... you can see the melted positions: #27 and #16. These are where most problems occur, as #27 is the 12 gauge wire from the Starter Relay lug [connected to the positive post (+) of the battery], and #16 is the 12 gauge wire from the Alternator lug [charging line].

To remove the terminals for inspection and cleaning/repair, insert a small regular screwdriver blade into the slot on the connector (to the left side of each terminal in the above picture) to release the little tab, while gently pulling from the back. This I did while the entire interior wire harness was out of the truck, and I gave the entire fuse block a good cleaning too.

Next I worked on the engine-side "insulators" [that's what Ma-Mopar calls them]. If yours are melted, or the locking tabs are broken, now is a great time to replace them. Four of these insulators are readily available new reproduction, from the left in the above picture:
1. Engine Wiring Harness Terminal: for 70-74 E-Body/71-74 B-Body/75-76 A-Body (On our Trucks, these are "Front End Insulators")
2. Cannot find these aftermarket, but on our Trucks these are "Engine Wiring Insulators"
3. Headlight Wiring Harness Terminal: for 70-74 E-Body/71-74 B-Body/75-76 A-Body (On our Trucks, these are "Chassis Insulators")
4. (top) Transmission Wiring Harness Terminal: for 70-74 E-Body/71-74 B-Body/75-76 A-Body (On our Trucks, these are the "Left Side Index Insulators" and are not normally used)
5. (bottom) Wiper Wiring Harness Terminal: for 70-74 E-Body/71-74 B-Body/75-76 A-Body (On our Trucks, these are the "Right Side Index Insulators" and are not normally used)

Also, the foam gaskets that insert into these, and go around the bulkhead connector, are available - the 1975-76 A-Body Mopars used the same parts here, and they are very inexpensive.


Here are a series of pictures detailing the removal of the terminals from the connectors/insulators.
The black foam gasket has been removed using a small pick to lift it up and out, and here I show how to put pressure on the spade terminal to unlock the tang. This one isn't too badly corroded (but see the #16 terminal, fried into place!? Poor conductivity was the likely culprit of the melted wire and plastic!)Note: I am applying pressure on the side where the slot of the terminal angles toward. Do this while gently pulling the opposite end (wire side):



Here it is out of the connector/insulator; just a little cleaning and this one will be good to go. [Don't ya just LOVE the PO's attempt to 'fix' this by sorta-soldering a pigtail onto the big wire in slot #16? It was then prodigiously wrapped in electrical tape!]



Here was my cleaning station... some electrical contact cleaner, a small wire brush, and some dielectric grease for reassembly.



Here it is after a little cleaning... Then I spread the tang back out a little (with a little screwdriver), smothered it in dielectric grease, and re-inserted it into its proper slot in the connector/insulator. When in correctly, it will 'click' into place and not back out. Pulling with needle nose pliers helped.



Repeat for the other wires on that connector/harness, repairing where needed, and put the black foam gasket into place.
Pack the bulkhead connector slots with dielectric grease before plugging this in, and you will enjoy a trouble-free electrical system in your Dodge!

[soopernaut]

This thread should become a sticky or be placed in the technical writeups area.

[crusty]

That's what I was thinking as well. I did a similar thread over on a ford site I belong to when I redid my harness. It is handy, even for the writer, since you can forget stuff over time.

A little bit of general tech I have found: I bought a garbage Dremel knockoff from Harbor Freight. It doesn't have any power at all, but with a wire wheel, it is great for cleaning these connectors. It is easier than a wire brush.

Keep on writing, PwrWgnWalt!

[PwrWgnWalt]

Seventh Topic - Cab Clearance Lights (running lights)

This information can be used for any sort of additional clearance or 'parking' lights one wants to have on the truck.

On my W200, the PO had added cab clearance lights, but had butchered the wiring and added a toggle switch to turn them on/off. I wanted them to come on with the parking lights, with no fiddling around.

The wiring diagram shows the clearance light circuit connects into the Running Light circuit ("R", from the First Topic in this thread). There is a factory bullet connector in the Brown Wire at the headlight switch connector plug, so it is easy enough to make a wire to run up the pillar to the cab lights, adding both a male and female bullet connector at the bottom end and plugging it inline to the Brown Wire (it ends up being sort of a "T" connector). The factory uses female bullet connectors strung across the cab at the top end, since the clearance lights come with a male end.

[PwrWgnWalt]

Eighth Topic - Steering Column rebuild and Turn Signal Switch replacement

The parts book has all the parts listed, but finding them at a reasonable price left me feeling a bit like leaving it alone... but, since the interior was all out, what better time to fix the wobbly steering column and non-self-canceling turn signal switch? (the plastic canceling arms had long ago broken off)

First - I wanted to fix the wobbly steering column... it had extremely noticeable play (movement side-to-side, up and down). The PO had an automatic column in this 4-speed truck, so I got the correct column from one of my parts trucks. The wobble was caused by improper assembly - the retaining bolts/nuts were not engaged. The upper column bearing was no good in either of them, either. So, a call to my local Dodge Dealer had me the bearing in short order (had to reuse the rubber bearing insulator, so be careful with that part). The Service Manual has excellent instructions for column R & R. After cleaning and painting it went together easily. The hardest part was getting the old floor bolts out of the parts truck!

Now for a turn signal switch...NOS Turn Signal Switches are available if you look long enough and are willing to pay over $100 - sometimes well over that. Since this is one area a new, non-NOS part made of modern plastics makes sense, I began searching... I found a company called Shee-Mar, Inc (out of CO) that makes these for our trucks as part # SM-106. [These are also listed as fitting 67-69 All Mopar w/o Tilt wheel, 70-71 All w/o tilt and w/o hazard on column, and 69-71 Dodge Truck.]

The price was right; the only problem was the wire colors don't exactly match, so here's the color key (the company doesn't offer this, but apparently the colors do match on some of the cars?). The plug connector is on the passenger-side of the pedal support structure, above the brake light switch. The white piece has a prong attaching it through a hole in the support (if you can get to it, squeeze the inside nibs together with needle-nose pliers while carefully pulling out):

Wiring Harness plug.....................Function............................Shee-Mar SM106 Wire Color
Yellow/Black.........................Left Turn - Front.......................Light Green
Yellow..................................Left Turn - Rear........................Dark Green
White...................................Brake/Stop Lights......................White
Dark Green............................Right Turn - Rear......................Dark Brown
Light Green...........................Right Turn - Front.....................Light Brown
Red......................................Emergency Flasher....................Red
Dark Green............................Horn.......................................Black (OEM is also Black from the switch)
Orange.................................Automatic Trans selector lamp....(separate wire, you keep the original)

If you are replacing just the switch, removal of the steering column is not required. Quite an easy process, all things considered, and worth it to have the canceling arms doing their thing, IMHO

[Roxyflash]

I just tackled pulling one of these apart I have several terminal tools but couldn't find the right one I made one from a pair of tweezers to get the wires removed from the plastic connector what is the proper tool for the job as I need to take another one apart

[nytemuvr]

Eighth Topic - Steering Column rebuild and Turn Signal Switch replacement

The parts book has all the parts listed, but finding them at a reasonable price left me feeling a bit like leaving it alone... but, since the interior was all out, what better time to fix the wobbly steering column and non-self-canceling turn signal switch? (the plastic canceling arms had long ago broken off)

First - I wanted to fix the wobbly steering column... it had extremely noticeable play (movement side-to-side, up and down). The PO had an automatic column in this 4=speed truck, so I got the correct column from one of my parts trucks. The wobble was caused by improper assembly - the retaining bolts/nuts were not engaged. The upper column bearing was no good in either of them, either. So, a call to my local Dodge Dealer had me the bearing in short order (had to reuse the rubber bearing insulator, so be careful with that part). The Service Manual has excellent instructions for column R & R. After cleaning and painting it went together easily. The hardest part was getting the old floor bolts out of the parts truck!

Now for a turn signal switch...NOS Turn Signal Switches are available if you look long enough and are willing to pay over $100 - sometimes well over that. Since this is one area a new, non-NOS part made of modern plastics makes sense, I began searching... I found a company called Shee-Mar, Inc (out of CO) that makes these for our trucks as part # SM-106. [These are also listed as fitting 67-69 All Mopar w/o Tilt wheel, 70-71 All w/o tilt and w/o hazard on column, and 69-71 Dodge Truck.]

The price was right; the only problem was the wire colors don't exactly match, so here's the color key (the company doesn't offer this, but apparently the colors do match on some of the cars?). The plug connector is on the passenger-side of the pedal support structure, above the brake light switch. The white piece has a prong attaching it through a hole in the support (if you can get to it, squeeze the inside nibs together with needle-nose pliers while carefully pulling out):

Wiring Harness plug.....................Function............................Shee-Mar SM106 Wire Color
Yellow/Black.........................Left Turn - Front.......................Light Green
Yellow..................................Left Turn - Rear........................Dark Green
White...................................Brake/Stop Lights......................White
Dark Green............................Right Turn - Rear......................Dark Brown
Light Green...........................Right Turn - Front.....................Light Brown
Red......................................Emergency Flasher....................Red
Dark Green............................Horn.......................................Black (OEM is also Black from the switch)
Orange.................................Automatic Trans selector lamp....(separate wire, you keep the original)

If you are replacing just the switch, removal of the steering wheel is not required. Quite an easy process, all things considered, and worth it to have the canceling arms doing their thing, IMHO :dance

Good place, got one for a D100(#106) for my Challenger at half the price for what was listed for Challengers, they use basically the same harnesses (some wires are different colors) for trucks and Challengers. But the 106 didn't fit '67-'69s trucks, on my '68 D100 (made from pot metal and the wheel for the horn ring contact is 90 degrees off). I think it's a mistake in their listing. Talked to a CS person there and they said they would take the '67-'69 of that description. You think getting to that plug on the firewall is hard to get to on a truck, lots more fun in a Challenger, need to be a contortionist.

[PwrWgnWalt]

I just tackled pulling one of these apart I have several terminal tools but couldn't find the right one I made one from a pair of tweezers to get the wires removed from the plastic connector what is the proper tool for the job as I need to take another one apart

I used a very small regular screwdriver, pushed down each side of the connector and pried so it pushes in the little tab on each side. Used 1 small, jewelers screwdriver.