Exciter Wire Question

[AZDeuce]

Warthog

I checked the diode with the key on, both sides had 24V but still no light at #2 dash position.

But I have to take the truck in tomorrow for a smog inspection (opacity) as my registration expires on Thursday. So knowing that it will start a few more times, even though #2 Alt isn't working, I put the dash together, so I could drive it to work tomorrow and smog it after work.

So I start collecting tools and loose nuts and bolts from the engine compartment so I can take her and put Diesel in her, so I tidy'd up the engine compartment while she was running.

I saw the dual plug was off #2 Alt so I could keep checking the exciter wire for power, I didn't want it loose as, it might get up against something and melt and short out, so I plugged it in the alternator even though it didn't have exciter wire power.

For some reason I decided to check the voltage before I left to fuel her up. I had 14.5V at btry #1, But to my SURPRISE #2 btry showed 14.8V
I have NO idea what happened.....

After fueling her I came home checked the voltage one more time, I had 14.5V at #1, and now 14.5V at #2 as that btry was lower and needed to charge more, which accounts for the earlier higher reading.

I shut the truck off, then turned the key on I NOW have BOTH alternator lights comming on.

WOO-HOO!!

The problem is, I HATE when vehicles "heal" themselves and you don't know how, or why.........it seems that will always come back to bite you in the butt at the most inappropriate time!

But at least for this evening I'm happy!

 

[AZDeuce]

Warthog

Well the truck is definitely NOT healed!

I started her this morning, and both lights came on (woo-hoo), and went out when the truck started.......but I saw this little "milisecond" light up of the #2 light after it was running. I took off and made it to the end of the block and stopped, when I took off the light came on for #2, when I stopped at the next stop sign only 100 or so yards away, the light went out. I turned onto the main road and put my foot in it, and the light came on, and stayed on, and hasn't gone off since.

I car pool to work, so when I got to my friends house to park the CUCV, I shut it off, and turned the key on but now the #2 light DOES NOT work again. So that's where I'm at, at least I know the light circuit works occasionally, and so does the alternator......occasionally.

So I checked the Gen 2 Diode last night with the key on and got 24V on both sides, of the little transistor/diode looking thing. So where do I go from here?

Thanks!

 

[Warthog]

Did you clean junk off the two pin plug at the alternator?

And have you double checked the connections on the new wires?

Something is not making good contact somewhere.

 

[AZDeuce]

Warthog

I am off tomorrow, City of Phx Holiday, (Ceaser chavez Day), I am going shooting in the morning with a friend, when I return I will clean the dual plug, it did look very dirty.

I crimped the extended wires together, but put extra force on them when crimping, then tugged on them to make sure they wouldn't come apart. So I'm betting it's that plug.

I will report back once I clean that plug, and let you know if it changed her behavior.

On a side note, she passed emissions with flying colors! At least something is going my way.

 

[AZDeuce]

Warthog

Just got home, cleaned the contacts on the dual plug for #2 Alt, it was dirty looking. I scraped as far as I could get with a small knife, and hosed the crud out of it with brake shoe cleaner.

I hooked it up, and fired up the truck, but #2 light came on and stayed on even after it started, but it was VERY DULL compared to the #1 alt light which was it's usual bright self.

I took readings at both btrys #1 was of course fine, at 14.5V, but #2 was not charging at 12.3V. I wiggled the #2 dual plug with the multi-meter hooked to the btry, but it never flickered it just sat at 12.3V.

I checked the #2 exciter wire at the inside fuse link, both with the truck running, and with the truck off but the key on, and got NO readings at either time on the dash side of the wiring harness's brown wire with the white line. (where the power "should" be coming from)

So my guess the bad ground must be somewhere else, other than the plug. Where should I be looking next?.

 

[stampy]

I would check all the main grounds. Such as the grounds off the batteries to the frame and the frame to the block. The fact that you had an intermitant reading says that either it's a broken wire or a loose or dirty wire (or some contact that isn't quite making). You may have to get someone else to help and start the truck and go through and systematically move wires (carefully) till the light blinks off then have them yell so you know where the problem is (one thing is sure you will know your trucks electrical better than anyone) When I have this sort of problem sometimes I use a jump wire to make a temprorary connection between points where a wire is. We played **** trying to find a broken wire on a forklift at work untill I used the jump wire and found the bad wire in the harness. Good luck.

 

[AZDeuce]

Stampy

Well I've considered a "jump wire", for the #2 alt exciter wire......but I have no idea where to tap power off of, so that it would work properly when you turn on the key.

But I'm "GUESSING" (since I don't really have clue) is that maybe this is not a ground issue after all, and it is the power side of the exciter wire, as I have a (DULL) #2 dash light, but a dead #2 exciter wire.

So I "think" that's telling me my ground is fine, or, I wouldn't have a light at the dash,.....at least that's what I think it's telling me....?