Another electrical thread

[Vhyle]

So I don't hijack the other "Electrical" thread...

I cleaned all the bulb sockets and contacts on the instrument panel today. After reassembly, here's what I have that works:

Wait to start/water in fuel (same as before)
Gauge illumination
GEN2
Blinker indicators

I'm missing the sockets for the hi beam indicator, and the center illumination. Seatbelt indicator is missing a bulb. All other bulbs are good.

Nothing else works.

Now, when on KOEO, ALL of the indicators should be lit, correct? Oil/coolant/seatbelt/GEN1 and GEN2, etc. Everything?

With the test light, I checked each contact on the instrument panel harness, and most of it is getting power. Both GENs (one is brighter than the other, so I'm assuming one is getting 24v and the other 12v). Hi-beam indicator is also getting power, although I'm missing the bulb socket for it.

The voltmeter wasn't working before, but I found that the 10a fuse for it was blown. One of the terminals on the gauge was loose, which is probably what caused the fuse to blow. I replaced it and tightened the terminal. I haven't driven it yet so I don't know if it works for sure yet.

I know both GEN lights are supposed to illuminate on KOEO. Is everything else supposed to as well?

Another thing to note is that I rebuilt the driver side alternator, and its output is great. The pass side alternator still needs to be rebuilt, since it's not doing so well. This is still main priority. I'm mostly asking about the lights right now.

 

[trukhead]

I will be installing and trouble shooting the wiring in the cab to an M1008 and an M1028 so I will chime in when I find out info.
I will observe what is happening on a couple of perfect running ones when I start them for clients to observe.

 

[Vhyle]

Another question - the alternator that I rebuilt is GEN1; the driver side alt.

With my voltmeter across the terminals, however, the rear battery shows 14.4, and the front battery was showing 11.7. Since ALT1 charges the front battery, I thought this was kind of odd, since it's practically new. But could this still be explained if ALT2 wasn't healthy?

 

[Warthog]

Did you reinstall the ground wire for GEN1?

The voltage for GEN2 is reading correctly.

 

[Vhyle]

Here are pics of GEN1 and GEN2, respectively

EDIT: On second thought, the previous owner had made a ground wire for GEN1 that ran from the rear of the alt, to a bolt that was bolted in the bracket right above the alternator. I removed it since 1) he didn't really sound sure if it did anything and 2) it seemed unnecessary. But I'm wondering if that's the issue after all...

 

[Warthog]

The stock alternators do not use the case as a ground. That is why they are called "isolated ground".

You have to have a ground wire from the GEN1 ground stud to the engine.

The passenger alternator uses the 12v output of GEN1 as its ground input. The 12v from GEN1 and the 12v output of GEN2 combine for 24v.

 

[Vhyle]

Ah, gotcha. The "isolated ground" concept is still pretty new to me, so I'm definitely learning something new every time I get under the hood of this thing. Sounds like I know the next step.

After that, the instrument light problem is next.

 

[Vhyle]

Alright so I re-attached the ground wire to GEN1. We'll see if that fixes the problem. Right now, batt 1 is on a charge. I drained it a bit with all the electrical testing I've done.

As far as the instrument lights - no fix yet. We'll see after the battery is good to go, but nothing has changed.

I looked over the fuse panel again, and noticed that my heater fuse was blown. In fact, it was a skeleton of a fuse left - there was melted plastic in that fuse holder. I pulled the blades out, cleaned out the plastic (broke it apart with a pick and dug it out, like a dirty tooth). With key off, I checked that circuit - nothing. Key on, blower off, nothing. Key on, blower on - there was power to the circuit, but not overwhelming. Nothing out of the ordinary. There's no draw on that circuit. My guess is that with the previous GEN1 malfunctions (since that circuit is tied in with GEN1), there was a surge of some sort and zapped the **** out of that fuse. That would explain why I have no heat.

Got a new fuse in. We'll see what happens after the battery charges. I'm going on a test drive later on. I feel like I've done a lot of digging around in this truck, but got very little accomplished. One thing at a time...

 

[firefox]

Missed the previous posts for some reason.
disregard.
Bruce

 

[cpf240]

Um, the heater fuse is shared by GEN 1... so if that fuse was blown, that may account for no GEN 1 light or charging.

 

[Vhyle]

Um, the heater fuse is shared by GEN 1... so if that fuse was blown, that may account for no GEN 1 light or charging.

Right, that's what I've learned from today's experiences. I replaced the fuse, but right now I have the front battery on a charge. So right now, I don't have a definite answer on if it was fixed since I haven't driven the truck yet, but chances are pretty likely that it is.

My worry is why the fuse melted away, and that fuse socket was almost melted shut by the fuse box's plastic. Like I said, I checked it for shorts/draw, and it seems to be fine. I'm hoping it was just a huge spike from the alternator, perhaps from the old diode which could have been faulty. I rebuilt the alternator so we'll see.

 

[Vhyle]

Started it this morning and drove it to work.

When I first got it running, I checked the batteries and alternator.

Front battery: 14.5v
Rear battery: 12.5v

Driver side alternator is putting out 14.5v. I didn't check output of the pass side alternator, but I suspect it's not good. I already planned on getting a rebuild kit for it regardless.

Blower motor - with new fuse, still doesn't work. I turn on the blower and the GEN1 light comes on. It did this before I made any electrical repairs to the truck. I'm guessing there's a short somewhere in the circuit, maybe in the switch?

Voltmeter - still doesn't work. It had a blown fuse. While I was reinstalling the instrument panel, I accidentally arc'd the voltmeter on the dash, which probably popped the new fuse. I haven't checked the fuse since, but I'm going to when I get home.

Still no dummy lights on key turn.

So basically I've gotten nowhere.

 

[Vhyle]

After the drive home, I checked the voltage on the battery terminals again. 14.1 and 14.5. So it looks like the alternators are finally doing their job. Is there a reason why it was only reading 12v this morning, like the regulator is on a delay or something?