5 replies to this topic

[sigmfsk]

Hi all:

After explaining my thought process, I attach some pictures and ask if someone can help point out what some components are in my engine compartment.

After redoing the engine to run via a FAST XFI EFI computer with dual sync distributor
FAST? - Sorry...
I won't need the electronic ignition module.
I probably won't need the ballast resistor either.

And if I use a newer style alternator
Lightweight Alternator Retrofit Kit-440 Source
AR Adapter Kits
Denso Lightweight Alternator & Bracket Pkg.
I won't need the external alternator voltage regulator.

I'm attempting to determine exactly what electrical components in the engine compartment I need to keep, and the piece that I think I definitely need is the ammeter shunt wire.

Looking at the back of the instrument cluster, the ammeter is clearly not receiving full current - as the small gauge wires couldn't handle it. It must really be a voltmeter, or an ammeter using a shunt.

I think that the factory service manual shows that the gauge is an ammeter with a shunt, and the associated ammeter LED is a voltmeter.

page 8-48

The ammeter L.E.D. [which is in the lower left area of the ammeter gauge] works independent of the ammeter indicator. It monitors system voltage. When the system voltage drops to a predetermined point, indicated by the ammeter pointer in the discharge area, the L.E.D. will illuminate and alert the driver...

page 8-54

Ammeter Test (Shunt type)
(P-D-C[body]-Y)
With the shunt type ammeter, the main car current is in a separate lead located in the engine compartment wiring. A small portion of the current is tapped off to supply the ammeter.

But then that same section says:
> CAUTION: Do not connect any accessories to the ammeter studs...
and there are no studs on the Monaco instrument cluster, so I'm not confident in what's going on here.

I'm thinking of going to see Bruce (of Bob's speedometer) next week and having him refurbish/check my instrument cluster, and maybe he can tell me what type of shunt is needed to correctly drive the ammeter. I'll also have him verify the separate oil pressure / water temperature gauge.

I did a quick look for a "shunt...separate lead located in the engine compartment wiring", and thought to ask about all the electronic devices that I could see, as maybe all of them can go away, or maybe some are important that I need to keep on my list. The only one I felt confident about is "f", the starter soloenoid. I throw in a bonus of the "d" (the presumably vacuum operated valve) in the hot water line. I've never seen one of those before. Its not electric, but it seemed weird.

All thoughts appreciated on part naming, ammeters, shunts, components I forgot about, etc.
thanks,
arthur

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[sigmfsk]

I found most of them:

a - ignition module

b - ballast resistor - PN#3874767
Bill Rolik Enterprises - N.O.S., Reproduction, and Replacement Chrysler Parts

c - unknown - marked 38713

d - presumably vacuum operated valve to stop hot water from entering the heater core when the heat is turned off

e - factory starter relay : PN#2444442
Bill Rolik Enterprises - N.O.S., Reproduction, and Replacement Chrysler Parts

f - aftermarket starter relay

g - voltage regulator : PN#3438150
http://mitechignition.com/html/pdf/2008MITECH.pdf


c is the mystery part.
It has three wires coming out of it. One connects to ground, the other two go to a weird connector that is not connected to anything. The loose connector was down by the voltage regulator. It was tied in with the regular wiring harness, so whatever it was connected to was probably down there.

It has the number 38713 printed on it, along with the MOPAR pentastar.
I couldn't find anything about a part like this, other than these two posts, by the same guy:

Slant Six Forum, :: View topic - '74 duster dash gauge panel insert
Slant Six Forum, :: View topic - Duster Heater Blower won't Work

I attach some pics.

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[bluzman]

Sounds like you have a cool project brewing there......the plug that is shown in your pic #3 was not connected to anything on my 74 Monaco. I found the part shown in your first two pics in an old manual I have at the house, but I cannot remember its technical name, I will get you the name of it tonight when I get home and re-post it. I had tons of electrical problems with the first 74 I had....mainly would not charge...replaced all the big parts..alt. VR, ballast resistor, etc. No Joy! I also ohmed out all wires that I could get to under the hood.... which led me to the instrument cluster. My cluster did not have the red LEDS on the fuel/ammeter gauge...but I did find a burnt spot in the printed circuit on one side where the ammeter pushes in. Also found the voltage regulater was fitting quite loosely in the back of the cluster. Brought the cluster to work and fully dis-assembled and repaired the burnt spot on the printed circuit. Also, removed the Voltage regulater and squeezed the terminals that hold the V/R for a tighter fit. I removed the whole underhood harness and fuse box/dash harness and began to ohm out every single wire......Yes..PITA. But I found 3.... 12 Volt constant/battery wires that were slightly chaffed from the metal dash...I installed some shrink sleeve over the wires and re-installed the harness and was quite happy to see 14.5 volts on my voltmeter...Finally! Hope this info..helps you out Arthur! Steve

[bluzman]

Arthur, Looks like that component is called the field and load relay according to a 1975 Dodge Monaco schematic. It shows 4 wires coming out of it..black/red..brown...black...and dark blue. Brown goes to starter relay....black goes to the pair of dk blue wires that feed into the dual factory fusible links.......black/red goes to the voltage regulator "f" terminal and the "f" terminal on the alternator...the dark blue splits and goes to one side of the ballast resistor plug and the other to the ignition module pigtail. Your picture only shows three wires.......what year is your car?

[sigmfsk]

> Looks like that component is called the field and load relay according to a 1975 Dodge Monaco schematic.

Thanks Bluzman. My Monaco is a '74. The connector was hanging out down by the alternator / voltage regulator, so it makes sense that it was connected there, even though I couldn't find a "field and load relay" on the '74 wiring schematic. Maybe it was not installed at the factory, but added later, like the non-stock secondary starter solenoid. The short story is that with your help I've convinced myself that I don't need this part since I'm rewiring the ignition and charging system.

thanks,
arthur

[sigmfsk]

I still don't know what the mystery part © is here:
http://www.bluesbrotherscentral.com/forum/bluesmobiles/10252-electrical-things-engine-compartment.html#post110905

but I don't believe it is a Field and Loads relay.

I found a relay on my '76 (pic 1), labeled 3843295.

This site:
http://www.arizonaparts.com/partlist.txt
seems to say that this is an A/C relay
4049132 A/C RELAY & BRACKET 3843295 SOP 1976 R,W,X,S
and maybe it was on R,W,X,S cars, but on D it is a Field And Load relay.

I tracked through the '76 wiring diagram until I found the connectors that matched what plugged into the relay.
Connector CE44 connects to the "FIELD RELAY" (pic 2).
But the wiring diagram shows this as "FIELD AND LOADS RELAY" (pic 3).

This isn't on the '74 wiring diagram. It looks like the purpose of this is to provide power to things when the starter is active.
It provides power to:
- leece neville alternator (not present with the standard alternator)
- external voltage regulator
- air conditioner vacuum switch

I plan on using the wiring harness from the 75 in my 74, so I'll include this relay, even though it looks like it doesn't do much.

I see that the "buffalo" fire department monaco
http://www.bluesbrotherscentral.com/forum/bluesmobiles-sale/9158-usa-1974-chp-spec-monaco-buffalo-ny.html#post103336


has the mystery device © to the right of the ballast resistor, in the same place as mine, but the owner doesn't appear to be on the board much. Note that buffalo and mine have the mystery device, and buffalo has the larger alternator, but mine does not.

your friend in not forgetting about mysterious parts,
arthur

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