Electrical

[PeeWeeQ]

A month ago, my passenger side alternator started making noise. Nasty grinding and rattling. Bearings were obviously shot and I knew it was bad. I ordered the $44 rebuild kit from CUCV Electric, disconnected the belt, and pulled of the alternator. I just made sure I kept the rear battery charged.

I rebuilt the alt (following the step by step on CUCV electric to the tee) and put it back on, but every time I tried to connect the rear battery, I got the "you've got this backwards" sparks. I did see a little smoke come from the firewall toward the top in the middle.....

I finally figured out that I did connect the alt wires backwards and put them on right. Good to go, right? Not so much.

I thought maybe I smoked the 10A fuse for the gen 2 light and the Volt guage, but, it was good, except, no Gen 2 light. Voltage I was getting from the back of the alternator was around 11.8 V. I didn't have the time and didn't know what to do, so, I kept going the way I was. On to some military training for a few weeks.

Now, I think that rear battery is shot. I can't get it to keep a charge at all and I have to jump it every time. Any idea where to start? What did I screw up (other than the bad reverse alt hookup?) That is, what did I fry? Or is it possible, this whole time, that the rear battery was bad as well?

Where to begin?

 

[MarcusOReallyus]

It's possible that your fireworks show caused a short inside the battery. If that happened, it's toast. I suggest getting it load tested, then go from there.

 

[cpf240]

If you saw smoke around the firewall, I'd say its time to check the fusible links.

 

[PeeWeeQ]

Thanks guys!

I had the batteries load tested last night and they are both good (just not charging). So I started cleaning terminals, bus bars, and everything electrical. I've found a couple of fusible links that are suspect, so, I'm replacing them and CLEANING, CLEANING, CLEANING!

This little crisis has forced me to really look at the wiring diagrams and learn the electrical system better. Hopefully, I get this all figured out.

Also, I am wondering, what the heck is this? It was between the pos and neg bus bars. I'm thinking it's just a noise suppressor, and, if it is, I'm just gonna leave it out.

 

[Warthog]

Noise suppressor. Not needed.

 

[PeeWeeQ]

Also, in the interest of checking the simplest things first, the upper bolt on my pass side alt sheared off at some point leaving me with no tension in the belt....DUH! That just MIGHT explain my charging problem....

Thanks for all the info, gents....

 

[MarcusOReallyus]

Yeah, that just might do it!


I once dragged my best friend over to give me moral support and hand me tools while I tore into my Datsun to try to get it to start. I was pretty sure it was a carb problem, as I had already checked the electrical side of things. It was cranking fine, and had good spark.

I was about knee deep into it when my not-mechanically-inclined buddy asked,


"Are you sure you have gas in it?"



Bad words followed.

 

[PeeWeeQ]

Alright,

So, I took the pass side alt out (the bolt had sheared off somehow, causing a loose belt), drilled the old bolt out, and put it back in. I charged up both batteries. I cleaned all of the bus terminals and battery terminals.

So, I get everything hooked back up and fire it up. I have 12.84 Volts on the driver's side alt (right on the back), and -.27 Volts at the back of the pass side alt. What???!!! In addition, I haven't had a Gen 2 light for a while, but now, I don't have a Gen 1 light either.

If I am interpreting some of the reading I've done correctly, it looks like having bad Gen light bulbs can cause the alternators not to work.?.?

So, the 10A fuse in the fuse block is good. If I check the bulbs and they are good, then what? Fusible links? I was going to replace them anyway, but, I am having a heck of a time finding them in parts stores (I've actually only been to a few and there are a lot in my area [Eau Claire, WI]), which leads me to another question--

--does anyone know which parts stores carry a decent supply and variety of fusible links? We have most of the big-name stores around here and I've checked Advance Auto Parts and Carquest. The kid at Advance yesterday had no idea what I was talking about. He kept bringing me inline fuse holders and was getting frustrated, so, I just gave up. They didn't have any in the isles.

 

[MarcusOReallyus]

If I am interpreting some of the reading I've done correctly, it looks like having bad Gen light bulbs can cause the alternators not to work.?.?

Yes, that's correct. GM, in their infinite lack of wisdom, decided to make the resistance of the warning light part of the charging circuit. Blow a bulb, lose charging.

 

[Hasdrubal]

Most of the time the bulb is good, its the contact between the bulb holder and circuit board. Try turning and re-installing the holder.

 

[PeeWeeQ]

Thanks Guys! I'll check the bulbs and connections and let you know how it goes....Simple stuff first, right....NOT ME!

 

[rosco]

The bulb allows a certain amount of juice to enter the alternator, creating an electrical magnetic field which is needed to produce electricity. Blow tyhe bulb (or bad contact, as stated), and the system is out. Hang in there, you'll get it.

 

[PeeWeeQ]

OK, I'm narrowing it down...

I cleaned the daylights out of the connections for both the Gen 1 and Gen 2 bulbs. Got the Gen 1 light to come on but, not the Gen 2 cleaned it some more (and double-checked the bulbs) but still no Gen 2 light. I checked voltages again and I'm now getting 14.97 Volts from the driver's side alt (overvoltage???) and 12.11 Volts from pass side alt. MUCH better than before, but not good enough.

Fusible link? Would one that hadn't completely burnt through offer enough resistance to keep the Gen 2 light from lighting and the voltage too low? I'm not sure, and, I still need to go out and find some fusible wire....

Thanks again, Gents for your input!

 

[PeeWeeQ]

I was looking at the schematic from CUCV Electric again, and I saw a "Generator 2 Relay". Can anyone tell me where it's at and what effect it would have if it had gone out?

 

[MarcusOReallyus]

I'm now getting 14.97 Volts from the driver's side alt (overvoltage???)

Nope. Healthy.

 

[cpf240]

I was looking at the schematic from CUCV Electric again, and I saw a "Generator 2 Relay". Can anyone tell me where it's at and what effect it would have if it had gone out?

On the back of the panel at the bottom of the dash where the STE/ICE diagnostic port is attached. There should be two small relays mounted next to the starter relay. If you've done the doghead mod, then you know where to find them! One small relay is for GEN 2, the other is for the voltmeter. You can swap them if you suspect one is bad.

 

[Vhyle]

Speaking of electrical, I have some issues:

Only about 20% of my instrument panel works. Speedo, gas gauge, gauge illumination and GEN1 light. WTS/WIF lights also work. Nothing else works.

I just pulled the instrument panel and cleaned all of the sockets, bulbs and socket holder contacts. I checked all the bulbs as well. Apparently, I'm missing two sockets, and a bulb. I put it all back together, and still nothing. Same as before.

Since I am missing two sockets, will this cause the rest of the panel to not work properly? I would imagine it causes an incomplete circuit of sorts, but I'm not 100% sure.

My pass-side alt also isn't up to snuff either. I rebuilt the driver side alt and it works wonderfully now, but not the other one. I'm trying to find out if the p/s alt needs to be rebuilt as well, or if it's just the GEN light circuitry that's not allowing it to charge properly.

 

[PeeWeeQ]

Some questions after hours of reading...

If the bulbs provide (Gen 1 and Gen 2 bulbs) resistance for the exciters to work and for there to be voltage, then, am I correct in assuming that my exciters must be working since I at least have around 12.25 Volts on Gen 2 and 14.97 on Gen 1? The bulbs are tested and good, the Gen 1 light works, and the Gen 2 light STILL won't come on. So, could it be one of those relays under the dash? I found and ordered them from CUCV Electric since they were less than $10 including shipping. On the site, they say that that's the problem in roughly half of the vehicles that have the voltmeter/Gen 2 light issue (my voltmeter has been between the yellow and red since this problem started).

Vhyle--good luck with your troubles and let me know if you find anything out. I've come to this conclusion: whether the bulb is good or not, if the Gen 2 light doesn't come on at all, you have an issue in the Gen 2 circuit...somewhere...

 

[cpf240]

I'd suggest doing the checks in the TM for the alternators. They have been posted here many times. Measuring the voltages at the exciter plugs, etc can help narrow down the problem.

As for the bulbs in the instrument cluster not working, one bulb should have no effect on the others. I've read posts here where people have been able to get replacement bulb sockets at the common auto parts stores. You might want to look in the -20p or -34p parts manuals to find the GM number, and then do a search at your local parts house website.

 

[Vhyle]

I came back to correct my post. Like an idiot, I didn't have the **** instrument harness connected after I reinstalled the cluster... oops.

So right now, I have GEN2, WTS/WIF, and illumination that work. Turn signals work as well (they did before, however).

I was testing the harness connector for the instrument panel, and it is getting power, but not to all of them. I'll have to look at the wiring diagrams and identify each contact on the instrument panel harness, I suppose. Looking through the TMs so far, I've only found out what a few of them are. I'd like to know what the entire harness is supposed to be sending power to.

EDIT: Nevermind. I found out the rest of the wiring for the instrument panel harness. I'll go from there.