Mando 55 amp alternator wiring diagram

[rjthompson]

Does anyone have a wiring diagram for a 55 amp Mando alternator w/internal regulator? Model no. is AC155603. I'm doing the engine wiring harness upgrade and cannot go by the wire colours for identification. Not sure if this is the original alternator or a replacement.

[KWKloeber]

Bob that's not the OEM Motorola alternator.

I hope it's not the CD harness "upgrade"? 
Are you replacing an ammeter also, or just the gummy bear plugs?


You should have the following on the alt/harness

alt Field excite (purple harness wire):
OEM was 16 gauge purple wire - could be on a post on the alt, or a "Packard 56" terminal (on typically a yellow wire off the regulator.)

Charge wire: Was orange harness wire
Alt out, Batt, +, Pos, etc.  -  - OEM was 10 gauge orange - could be red now to the solenoid.

Tach signal
"A/C", Tach, etc.  - OEM harness wire was orange or gray

Could have a Voltage sense wire - goes to a battery or to the solenoid?

If you post or email me a pic  I can help ID the Alt wires for you.


Ken

[KWKloeber]

Bob,

Follow up on the Mando terminals -

Holding the Mando "UP" (i.e., foot at 6-o'clock, adjusting tab at 12-o'clock.)

Alt 10 o'clock - A/C tach tap post (Harness 14 gauge gray)
Alt 2 o'clock - Alt out, batt charge post (Org or Red to solenoid)
Alt 4 o'clock - alt frame ground post
Regulator 9 o'clock - alt field excite wire (harness 14 gauge purple wire)
regulator 3 o'clock - battery voltage sense wire (should be a red wire to solenoid or direct to batteries)


ken

[Stu Jackson]

Alternator Regulator Wiring Diagrams - all three http://c34.org/bbs/index.php/topic,4548.0.html

[rjthompson]

Awesome, thanks Ken! I just needed a cooler head to help. I have managed to identify the terminals on the alt: Ex. - excite, S - sensing, Output and Ground. That just leaves a badly corroded (holding my breath) terminal with a pink wire on it, which must be the tach wire.
I had to replace the engine control panel cw/voltmeter and since I got it from CD, I just ordered their wire harness as well. I took one look at the terminal blocks supplied and decided to wire straight to engine without a disconnect point.
I think I'm in business now! Do you have any other tips/tricks that might keep me out of trouble?

[rjthompson]

Hey Stu, missed your response while I was replying to Ken. Thanks for the drawings!

[KWKloeber]

Awesome, thanks Ken! I just needed a cooler head to help. I have managed to identify the terminals on the alt: Ex. - excite, S - sensing, Output and Ground. That just leaves a badly corroded (holding my breath) terminal with a pink wire on it, which must be the tach wire.
I had to replace the engine control panel cw/voltmeter and since I got it from CD, I just ordered their wire harness as well. I took one look at the terminal blocks supplied and decided to wire straight to engine without a disconnect point.

Bob,

If the badly corroded is at 10-o'clock, you are onto it!  I believe the OEM harness was an unnecessarily large 10 gauge sometimes orange (mine), sometimes gray wire.

Wise move replacing the engine end wires!!  Though that cost you about double of straight wire.  The last bare bones harness I did was $120, and that was fully terminated, drop in, plug and play.  Are you doing the same (hopefully) on the panel end?  Using all FTZ heat shrink terminals?

you have any other tips/tricks that might keep me out of trouble?

Yes, depending on how much time/effort/expertise you have. 

(in no particular order/priority)

Rewire panel with all marine grade terminals.
Zip tie the harness securely so there is no movement/stress at terminations/switches/gauges
Protect the power lead to the panel from over-current.
Put a large ground cable on the alternator frame.
Larger charge cable to the solenoid.
Move the battery negative from the bell housing to a starter bolt.
DON'T use a manifold stud for the harness negative.
Install a ground buss for the harness, Alt frame, other negatives, etc.
Bond the oil switch/temp sender (and temp switch if you have one) to prevent faulty readings due to poor grounds.

I could go on and on......

Oh, and the ever famous, fix the stupid terminal/connection used on the solenoid for the "S" wire.

ken

[rjthompson]

I've already done quite a few of the items on your list during the complete re-wire I am doing on the boat. Not sure about the bonding of the alternator frame and oil/temp. senders... Haven't read anything about those! Do I need a heavier wire on the alternator ground terminal as well?
Used adhesive lined shrink connectors for the harness at panel end and will do the same at engine end. Is there a kit to upgrade that spade connector on the starter solenoid?

[KWKloeber]

Not sure about the bonding of the alternator frame and oil/temp. senders... Haven't read anything about those! Do I need a heavier wire on the alternator ground terminal as well?

Is there a kit to upgrade that spade connector on the starter solenoid?

The alt frame cable should be the same gauge as the charge cable.  Depending on the alt capacity and future upgrade, #8 minimum, #6 or #4 are better.

w/ my harnesses I started bonding the switch, oil pressure sender, temp switch, temp sender because the thermostat cap is subject to the ground going bad (gasket between parts, bolts threads, bolt heads corroding.  Belt and suspenders.as I like to things once and be done with it forever.

When the starter solenoid goes south, I replace w/ a threaded post S terminal .  Otherwise until then, I handle that failure point by crimping up a 6" pigtail w/ a bare quick disconnect, and a fully insulated male QD.  Solder the female QD onto the solenoid and heat shrink over it, put a fully insulated female QD disconnect on the harness wire and connect 'em up.  WITHOUT an inline fuse,  It's unnecessary if you fuse the panel wire (which should be done), and a fuse there can be another failure point.

Note that the fuel pump and alt excite wires are redundant and dumb.  I run one for both (which is what Wb figured out to do on the B series engines.)

How did you fuse the panel power wire?


-Ken

[rjthompson]

The fuel pump is noticeably absent from CD's wiring diagram. Did you just run a jumper from the Alt/Excite terminal to the fuel pump?
I think I will buy an Ancor 30 A. inline fuse holder and run from the starter solenoid to the panel. Most of the drawings I've seen do it that way.
Thanks for the heads-up on the alt. frame ground, the existing one is #10 and petrified like a piece of rebar!

Bob

[KWKloeber]

An inline fuse like that isn't what you want - and I don't think it's good for 10 awg.
I'm looking at 2 dozen fuseholderd right now.

PM me your Asst and I'd be happy to send you the setup.

I'd love for you to send or post a diagram that shows a fuse in the power feed at the solenoid. One has never been installed by Universal. On the "S" wire, yes. Which is at the wrong end of the harness anyway.

I make up a custom QD terminal to crimp onto the Motorola alt yellow excite wire, one feed, the other runs back to the lift pump. In your case, you'd just run a wire back from the alt excite post.

You need the engine schematic, not CDs worse idea schematic. It's in the engine manuals on the TechWiki.  What engine do you have?

-kk