Rethinking The 3G Conversion Pages/Process

[Gary Lewis]

Folks, I'd like to start a debate here on what we should be recommending and have documented regarding 3G conversions.  (I want to keep this to "3G" rather than 1-wire as that adds complexity.  We can address the 1-wire after we sort through this.)

Our recommendations and schematics have been for a significant changeout, including a megafuse, voltmeter instead of ammeter, and a key-on relay.  But many people want to convert w/o doing all of that, so I'm beginning to think that we need to have three or four different scenarios.  Something like the following with advantages, disadvantages, and schematics included:

Quick & Dirty: This would be for those that want a 3G but don't want to do any other work.  In that case they could just take the alternator output to the starter relay - without a fuse.  I personally don't think this is a good idea, so maybe we shouldn't even mention it?

As for advantages and disadvantages, one disadvantage would be that the ammeter would only show discharge, so would be worthless.  But an advantage would be that everything would be there in case you wanted to go back with a 1 or 2G.

Bare Minimum: As above with a megafuse.  And maybe this is really "bare minimum"?  If so, should we ditch the Quick & Dirty approach?

Cleaned Up: In this case they could unplug connector 610, bring wire 37 (Y) from S101 to the battery + stud of the fender mounted starter relay, and bring the fused output of alternator there as well.  But you'd still have an ammeter that was worthless as now it'll never move at all.  And you can't easily go back to a 1 or 2G.

Done Right: This is the one we've been describing for years, with a megafuse, voltmeter, etc.  The advantage over Cleaned Up is that you can tell that the alternator is working because of the voltmeter. But a disadvantage is that you've now altered the wiring so going back would be difficult.

Maybe we don't need Quick & Dirty and just go with Bare Minimum as we can't recommend doing it w/o a fuse.  But I wanted to get that out there to see what y'all think.

If we had three or four options, with schematics and advantages/disadvantages, then we would be able to answer the questions we get of "but why can't we" do this or that.  We'd have thought through solutions that take into account "this or that", at least for the most part.  And then people could chose their poison.

Thoughts, please!  

[ArdWrknTrk]

Subscribed.

[BigBrother-84]

Gary Lewis wrote

But many people want to convert w/o doing all of that, so I'm beginning to think that we need to have three or four different scenarios.

No suggestion to share about any possible scenarios.

But if this section could include a “special chapter for lazy mechanics” I would subscribe, even if more expansive way to go.

I love the plug’n play upgrades, such as Daniel Stern’s headlights and pre-built harness/relays, or Lee steering pump, for example.

[85lebaront2]

Gary, if someone didn't want to modify the cluster, an aftermarket voltmeter could be installed under dash or in an A pillar pod. Voltmeters are a far better indicator of charging system health with an alternator, just be sure it is connected to an ignition switched source.

[BigBrother-84]

Bill, did you receive my January 9th email?

Talking about carb shipping…

[85lebaront2]

Apparently not, I couldn't find anything from you on 9 January 2024.

[ArdWrknTrk]

A decent voltmeter cost more than Rocket man's calibrated stock uni until the advent of cheap electronics from 'over there's

While it is a bit of a fuss to open the cluster and swap the gauge, you've got to admit it does look the part and you know it is properly tested.

I (personally) can't stand digital instruments.
Your brain doesn't need to process where a needle is pointing.
You don't even need to be able to read the numbers.

[Gary Lewis]

Bill - Yes, an aftermarket voltmeter could be added.  But I don't like non-functioning things on my truck, so don't want that gauge to sit there and do nothing.  So I personally prefer that the ammeter be converted to a voltmeter which, as you said, is a far better indicator of charging system health.

But if someone wanted to go aftermarket they could use the Cleaned Up approach, meaning unplug and remove the C610 harness and just add their own voltmeter.

Jim - It is a hassle to pull the cluster and swap the gauge out, but less hassle than stuck on the side of the road because the alternator quit and you couldn't tell.  Been there, done that.

And another hassle is wiring up the key-on relay.  So what about an option to power the voltmeter with the LG/R wire instead of a relay?  As you know, that's not my preference as I want to know the voltage at the battery and not in the cab, which fluctuates with the accessories that are on.  But some may prefer that over wiring in a relay.

[ArdWrknTrk]

Certainly making a U of wire and jumping 904 lg/r to 655 r/o on the cab side of C610 would make the most sense to anyone.

Cut 654 y/lg near the cluster connector C208A and take it to ground when you install the voltmeter (nee ammeter)
If there isn't a cluster ground there is one for the intermittent wiper switch or G701 behind the radio..

[Gary Lewis]

I'm not high on grounding 654 in the dash as there's not much room to work there.  However, it is an option and could be explained that way.

My preference would be to salvage the C610 connector from the removed harness and splice on some wire to the short piece of Y/LG there and take that to ground.  Then do the U there on that side of C610 for LG/R to R/O and, while at it, extend that wire to the alternator.  Similarly, use the piece of Y for Ckt 37 coming out of C610 and put a ring-tongue terminal on the end of it to go to the megafuse's stud.

All of that work could be done on the bench and then plugged in to the truck.  In fact, that is something that someone could make up and sell - a kit with a voltmeter from Rocketman and a C610 replacement harness and you'd have a plug & play 3G.

[ArdWrknTrk]

Well, I have to disagree.
But it's your baby. Draw what you want.

[Gary Lewis]

What part do you disagree with?

[ArdWrknTrk]

We've already heard in this thread that that harness is completely toast.
If it's garbage, get rid of it.

Less chance of hidden corroded wires or some insulation flaking off and starting a fire

[Gary Lewis]

That's why I was talking about options.  If the C610 harness is good, then you could...  But if it isn't then...

I think I have a harness that is good and much prefer soldering on the bench than in the truck, so would go that way.  But if the reader's harness isn't good then they'll have to do it another way.

Jeff said he loves "plug’n play upgrades", and I think he is probably typical of truck owners.  So if we can get it down to just unplugging the C610 harness and plugging in a replacement then I think a whole lot of people will want to do it.

[BigBrother-84]

You have my vote!

[Gary Lewis]

I thought you'd like that, Jeff.  

Here are my thoughts: I'll draw up a schematic showing how I think it can be done via a C610 harness.  But that's going to look more complicated than it really would be given the way the schematic has the 4 terminals of C610 spread all across the page.

Then I'll take a real C610 harness and make the needed changes and you'll see how simple it really is since C610 is really small.

But I'm in the middle of another project so won't get to this for a while.  In the interim I'd love to see everyone's thoughts on this.

[ArdWrknTrk]

I had to highlight all those different C-610 connector locations for another member not long ago (maybe ifitaintbroke/Bradley?)

While it certainly would be nice if you went into production of plug n' play harnesses Gary 😉 maybe it could make a good venture for the Blue Truck guy??
Sorry, I forget his name too.  (blame it on my face blind autism)

[Gary Lewis]

It would be great if someone would make them.  I designed the adapter that Tim Meyer is selling to put a ZF5 behind the M-block and am happy he's doing that.  And I'd be thrilled if someone started making a 3G harness for the Bullnose trucks.  I don't need nor want any recognition from it.

But I need to make a proof-of-concept first.  Hopefully I can get the two projects I'm doing on Big Blue at present, the new seats and relays for the HVAC blower, done soon and turn to this.

However, I'm drawing a blank on the Blue Truck guy.  Can someone remind me who that is?

[ArdWrknTrk]

Do you forget about the dash patch that Ron is profiting from???  

[Gary Lewis]

Yes, I'd forgotten about that.  But given the problems he's had I don't know that he's getting much profit from it.