Exciter Wire Question

[Mohawk Dave]

Among all these other items, make sure you thoroughly check all your grounds. Even if they look good, take them apart, sand, a(I apply dialectic grease) and re-install. Grounds cause many problems. Not saying this is a ground issue, but at least it would be PM.

Best wishes,

Dave

 

[Warthog]

When you arc'ed the Gen2, you may have blown one on the fuseable links or even the 24v fuse.

Time to breakout the voltmeter and check wires

IF you use a civvy alt for GEN1 you do not need the ground wire as the case is the ground.

 

[mistaken1]

Thanks mistaken1 I did not know that. I assumed as I had seen many with a plain alt on 1 and a isolated ground on 2 that's the way they were.

I learned that from reading the posts of the long time members around here. Just repeating what they have said.

It is a shame we cannot find isolated ground alternators for the same price as the off-the-shelf case grounded alternators.

 

[AZDeuce]

I didn't have a chance to work on the Blazer today, but just checked this thread. Thank you all for the good input.

Warthog I have replaced All of my fusible lnks, and I have power everywhere I'm supposed to so I don't think that's it.

And the 24 V fuse is fine but I had no power coming out of the fusebox for the 24V exciter wire (Alt 2) so that's why I ran the wire outside of the fusebox with a inline fuse, NOW I have power everywhere.

So here's tomorrows plan after I get home from the dentist: At this point Alt 1 WORKS and is an isolated ground model, I will pull the current non-working Alt 2, and put At 1 in it's place, as on my truck installing the Alt in the #2 position is a MAJOR PITA due to a civilian home made A/C intallation.

I pulled #2 Alt 3 times yesterday........I won't be doing THAT any more after tomorrow! I'll put the working #1 Al in the #2 spot and hopefully the #2 spot will no longer be a issue (HOPEFULLY!!)

Removng the #1 Alt is easy and takes about 5 minutes, so the current non-working #2 Alt will get rebuilt AGAIN.......but this time with the windings and armmeter out of my original #2 alt with the broken case.

I will install it in the #1 position, so at least if it doesn't work it will only take 5 minutes to pull it! Why I didn't think of this yesterday escapes me! I was probably to pis.....mad to think straight!

Anyway with the different windings/armmeter HOPEFULY it will now work, if not I'll just go buy a new civilian alt at AutoZone, put all of it's guts in my case along with the isolated ground stuff, and have a NEW isolated ground Alt.

I would ASSume at this point that will fix EVERYTHING and I can have my Blazer back!

I HOPE!!

 

[stampy]

May be time to try to hit up some of the AZ guys to see if someone could come by and you could look at their truck as an example. I have fixed many problems by having a good running example right next to me. With someone doing "home made a/c work" to your truck there may be wiring issues that shouldn't be there. Best of luck either way, wish I was closer.

 

[AZDeuce]

UPDATE to the UPDATE, 03-25-11

This is in reply to MY post above.

I swapped the good alternator out of it's #1 spot, and put it in the #2 spot. I put my old winding and armmeter in the bad altrnator and put it in #1's spot.

This time when I started the Blazer #2 battery was charging but not #1. This told me my unorthodox wiring to circumvent my burnt terminals at the fuse box was a success, both at the #1 spot as well as #2. It also told me I had a bad alternator.

So I bought a civilian Alt at AutoZone last night, and installed it tonight in the #1 spot after work, I then hooked up the batteries with NO arcs or sparks, then started the engine.

SHE LIVES!!!!

BOTH batteries are now being properly charged and both Alt dash lights are now off.

FINALLY!

Now I just need to put the dash panel back in her tomorrow, and hopefully I'll have my Blazer back!

Mongo HAPPY!!

 

[Warthog]

Congrats.

Now you get to learn how to rebuild an alternator....

 

[stampy]

Great Glad you got it running!!!!

 

[AZDeuce]

Thanks to ALL of you for all the replies and help.

Warthog......Actually, I get to rebuild an alternator for the FIFTH time! I'm getting pretty good at this! Sometimes they even work!

And while I'm still not fond of electrial work, I'm no longer scared.......you just have to get your hands dirty, and be willing to learn new things. Of course, I have to learn everything the HARD way! But I learned it.

My electrician friend explained it to me, but I still don't understand how on Alt # 2 you can put 24V into a 12V alternator and NOT burn it up, and yet it charges battery 2 at 14.5V.......but it does, thanks to the isolated ground, so I guess that's all I really need to know.

You can throw any civilian Alt in the #1 spot, but NEVER, EVER, use anything but an isolated ground Alt in spot #2.

Again, thanks for the help, and patience, to help this former electrically challenged scaredy-cat, rise to the occasion and wage war wth the electical gremlins that plagued my CUCV, and helped me overcome, and beat them!

I WON!

Blazer=0, Me=1

 

[stampy]

Kind of like how you can jump a 12v car off a 24v Blazer if you connect to only 1 battery. Ie the positive and negative of the same battery.

 

[AZDeuce]

I AM BUMMED!!

She's DOWN AGAIN!

I put in the dash, and started the truck, I had 14.5V at both alternators....all was well.

My truck had the starter relay and the other two plasric relays tucked up under the dash, along with the diagnosis plug. On one of the spare wiring harness I received it had the steel plate that all the relays fit on then it mounts to the inside bottom of the dash and two of the bolts that hold it in place, also hold the diagnosis plug. So I decided to hook up my relays on that metal strip and bolt up the diagnosis plug too, so my truck would be more original.

But first I had to remove some after market screws and bolts, that held a bracket for the AM/FM radio, and several small ground wires. While removing the bolt I had to use a ratchet, and I bumped something and made a SMALL spark.......but my heart stopped for a second "knowing" I had just fried my alternators AGAIN.

So I located what I bumped with the ratchet, and low and behold there was the VOLTMETER I thought my truck no longer had......COOL!

So I stopped what I was doing and fired the truck up boh alt lights worked, and I took a multi-meter reading, I still had 14.5V at BOTH alternators.......I DIDN'T fry anything! COOL!

So I DISCONNECTED the batteries completely, and continued to remove the bolts and install the sheet metal relay plate,
When I was done I fired it up but this time I had NO Alt 2 light at the dash.......what in the world? I had a light on both alternators a minute ago when I started it up to make sure I didn't hurt anything.

I started it up Alt 1 had 14.5V but #2 only had 12.3V! I shut her down pulled the dual plug at #2, and had 24.8V on the red wire. I turned the key ON, but got NOTHING on the brown exciter wire.

I had re-routed the exciter wires, and put inline fuses on them, but both fuses were good, so I checked the 24V fuse in the fuse box....it was BLOWN, so I replaced it, but what blew it?

So I turned the key back on and still NO Alt 2 light (#1 was working), I rechecked the fuse but it was good. So I figured the light had blown so I took the dash back apart.

I switched the bulbs back and fourth they ALL worked, but not at the #2 light position.
So I got out my multi-meter and read both copper strips that feed energy to the # 2 light.

On the bottom half (if I remember right) I got 24.3V, but on the top half I got nothing. I checked the volts on the working lights, and got power on one side but not the other.

I then tried reading both sides with a working bulb installed, but only got Volts on one side not the other

So I got NO # 2 dash light, nor power at #2 exciter wire, yet all the fuses are ok.......so where do I start looking at now?

DAZED BUMMED,& BEWILDERED in Buckeye!

 

[ohfisherman]

welcome to the club!! mine was down for 3 weeks too. i pulled the #2 alternator, took it to a great repair shop and it bench tested fine. ripped the whole friggin dash out, checked all wiring, checked relays, checked fuses, jumped relays, etc....you get the point. at the end my buddy says there is nothing wrong with anything in the truck or alternators. we were getting voltage from alternator but no #2 light...pulled my alternator from my other truck and POW!! everything working as it should!! i guess a bad diode trio will not show up on a bench test? i was in the rebuild shop when he tested it and it looked fine to me. anybody heard of if this is true? a ton of work for a $3.00 part. and big thanks to whoever did the big thread on chasing down these electrical demons. it helped a lot. but on a serious note, does anybody know why it would test could with a bad diode trio?

 

[stampy]

Time for a frosty malt beverage. Hope it is the diode.

 

[AZDeuce]

Probably isn't the diode, as I just have NO power to #2's excitr wire.......that's got to be the problem.

Everything was fine until I mounted all the relays on that plate. So after church this afternoon I plan to remove that plate and the relays from them, and see what I can sort out.....It's "GOT" to be something physical, hopefully I can SEE it and fix it.

 

[Warthog]

The 24v fuse blew because of the"spark" at the voltmeter.

From your description of the voltage at the blulb. I would clean the contacts at the bulb holder and maybe install a new bulb just for grins.

Pull the bulb holder and check the ohms at the bulb and the holder.

According to the parts manual, the GEN2 bulb is a 194 and the GEN1 is a 168. There are differnt wattage bulbs.

 

[AZDeuce]

Warthog.......well crud, I messed that up, as I was switching the bulbs around, and I don't know which one is which!........DOH!

ALL 4 bulbs DO work, but NOT in the #2 position, but yet I have 24.6V at that position but NONE of the bulbs work there! I can't understand that!

I am thoroughly bewildered at this point. I removed the sheet metal plate and twisted and played with the relay wires, but it changed NOTHING.

I took a V reading on the two smaller relay housings connected to the wiring harness. On one of them I got both 12 and 24 V readings on the other one only 12V

I have no idea which relay block is which, as they were just hanging loose, and I just stuck them on the sheet metal plate.

At this point I am EXTREMELY frustratated, as everything was fine yesterday even after the "short" incident.......but after hooking up the sheet metal plate I lost the #2 exciter wire.

Now I'm wondering where I could find a 24V source of power that only works when the key is on, so I can circumvent the light, and still have power directly to the exciter wire.

Any Ideas?

Desperate in Buckeye!

 

[doghead]

Have you touched, cleaned, checked the wire connection where the flexible circuit sheet(gauge circuits) connects to the wiring?

 

[AZDeuce]

Doghead.......No I did not clean the flexible circuit board, I wouldn't know how to do it for fear of bending and breaking a circuit.

I did pull the entire dash panel out and looked for a broken connection, but all seemed fine.

If I have power at the #2 light fitting (and I do!), and ALL my light bulbs are good (they are) WHY doesn't the light turn on when inserted in that position?

All the bulb does is complete a circuit correct? Of course if that's true.......then what makes it go off by itself when the truck starts?

 

[mistaken1]

Doghead.......No I did not clean the flexible circuit board, I wouldn't know how to do it for fear of bending and breaking a circuit.

I did pull the entire dash panel out and looked for a broken connection, but all seemed fine.

If I have power at the #2 light fitting (and I do!), and ALL my light bulbs are good (they are) WHY doesn't the light turn on when inserted in that position?

All the bulb does is complete a circuit correct? Of course if that's true.......then what makes it go off by itself when the truck starts?

http://www.steelsoldiers.com/cucv/66245-m1028-charging-issues.html#post799218

If you have 24V at one side of the lamp the other side needs a ground to have current flow.

When the alternator is producing power the emf generated on the 'ground' side of the lamp stops current flow through the lamp.

Do you have continuity from the other side of the lamp holder to ground? If not that lamp will not light when the key is on an the engine is not running.

 

[AZDeuce]

Where would I find the other end of the circuit boards ground?