Alternator not charging after repaint

[Tori]

Strange i know,..... had the car at the bodyshop for repaint, was there for 5 weeks. Now that it's back and i'm reassembling things, i notice the battery isn't charging. Battery going dead after several starts to move the car around, and volt meter shows no charge.

I did pull several fuses before taking it to the body shop to try to eliminate a draw it has so it wouldn't sit there and go dead on them, but now that they are all back in still no charge.

Anyone have any input, I assume it's just coincidental, but maybe i'm missing something.

 

[Tori]

I did just go do a little troubleshooting, Running, there is no output from the Alt. Also noted the idiot lights do not light when the key is turned to ON. Only the FASTEN SEAT BELTS light come on. So, there's a circuit somewhere that isn't being energized to light those functions, and probably no signal to turn the alternator on.

Does this info trigger anything ?

 

[whitehot1]

Might try turning the key to the on position and pressing in on the speedo/gauge panel to see if for some reason it's not making contact.

 

[Tori]

Thanks, i just tried that along with while the key was on, watching for the other idiot lights to light as i wiggled, pushed, pulled every wire i could get my hands on under the dash, relay panel, and as far up as i could reach behind the inst. cluster.

I did a bunch of reading on how the system works, and while i know my ALT light is not lighting, neither is any of the others in that left part of the cluster. I also have a single wire ALT, so i can't ground the brown L wire from the plug.

 

[Tori]

Pulled cluster out enough to unplug it, and push it back in while wiggling it, not lights.

I also notice i'm not getting a CHECK ENGINE LIGHT either,..... gonna go to the wiring at the computer next. They did have the lower kick panel off over there, and maybe something isn't making a connection at the computer. FML

 

[RmvBfrFlght]

I also have a single wire ALT, so i can't ground the brown L wire from the plug.

Since this is a one wire alternator without the use of the plug with the brown wire, the dash battery light is meaningless. It is all on the alternator, so my guess is that it is bad.

RemoveBeforeFlight

 

[Tori]

Since this is a one wire alternator without the use of the plug with the brown wire, the dash battery light is meaningless. It is all on the alternator, so my guess is that it is bad.

RemoveBeforeFlight

Yes, but how do you explain the lack of all the other idiot lights working. Clearly something in the harness isn't getting signal.

On the 1 wire alternators, how does that work.... is the excite wire just a 12v source ? And it no longer runs thru the dash light ?

 

[RmvBfrFlght]

A true 1-wire alternator has just that, one wire to the battery +. The connector with the brown wire isn't used.

In this case need to rev-up the alternator/engine before it will start to charge. And it won't matter what the other dash lights are doing. Note that the stock '86-'87 alternator can't be used as a 1-wire. It doesn't have the residual magnetic field imposed on the stator.

Can you post a picture of the alternator setup? That would be helpful.

RemoveBeforeFlight

 

[Tori]

Will do. As soon as i get home. Thanks for the help

 

[Tori]

Will do. As soon as i get home. Thanks for the help

okay,.... cool. its 120amp ! (pardon the dust..... remodel we must. hehehe -- errr i mean, just out of the bodyshop.)

 

[whitehot1]

So this alternator was on the car and charging with all the dash lights working when you took the car to the body shop for paint?

Just trying to understand what would have changed in 5 weeks with them just painting the car. Weird that is.

 

[Tori]

So this alternator was on the car and charging with all the dash lights working when you took the car to the body shop for paint?

Just trying to understand what would have changed in 5 weeks with them just painting the car. Weird that is.

Yea, you and me both. The only thing that i think it could be is the wiring to the computer. The computer kickpanel was taken down to get the lower A pillar trim out of the way, so maybe the wiring there was stressed at the computer connection. I'll have time tomorrow to take that back apart and investigate.

 

[RmvBfrFlght]

okay,.... cool. its 120amp ! (pardon the dust..... remodel we must. hehehe -- errr i mean, just out of the bodyshop.)

View attachment 298714

OK, not a 1-wire setup. Appears to be the stock alternator.

See the connector on the upper right on the alt (black with blue insert), that single wire is the brown one that goes to the dash battery light. If at key-on, engine-off the battery (volts) light isn't on then the alternator won't charge. Power to the light is from the gages fuse, so check that.

To check if the light not coming on is due to the alternator being bad, unplug that connector and using a jumper ground the terminal of that wire. Key-on, engine-off and the dash light should light up. If not then a wiring problem.

RemoveBeforeFlight

 

[Tori]

Thanks RBF, i was under the impression (from all the alternator posts i've read) that the stock unit was 105 amp, and the connector had 4 wires.... ???

I've checked all the fuses already so i know its not that. I'm really hoping its a poor connection at the computer harness.

 

[TurboDave]

Thanks RBF, i was under the impression (from all the alternator posts i've read) that the stock unit was 105 amp, and the connector had 4 wires.... ???

I've checked all the fuses already so i know its not that. I'm really hoping its a poor connection at the computer harness.

I doubt you'll find anything associated with battery charging or alternator operations at the computer harness.

 

[hotairgnx548]

okay,.... cool. its 120amp ! (pardon the dust..... remodel we must. hehehe -- errr i mean, just out of the bodyshop.)

View attachment 298714 View attachment 298715 View attachment 298716

tori where does the the wire with the yellow connecter go? john

 

[RmvBfrFlght]

Thanks RBF, i was under the impression (from all the alternator posts i've read) that the stock unit was 105 amp, and the connector had 4 wires.... ???

I've checked all the fuses already so i know its not that. I'm really hoping its a poor connection at the computer harness.

The stock '86-'87 alternator is a 120 A unit. That connector has the capacity to use 4 wires. But only one is used in our cars (bad move). The best way to wire that connector is such:

Use either the PowerMaster or fan delay relay feed from the fusible links (big red wire) and wire it to the large S terminal.
Grab the PNK/BLK wire from the EGR solenoid and wire it to the F terminal.
Leave the L terminal as-is as it may show when/if the alternator fails.

The S terminal is a sense line. Instead of regulating the voltage based on the internal voltage, the regulator will base the alternator output voltage from the starter feed. This improves overall vehicle voltage as it makes up for the drop in the cable between the alternator & battery. Plus any minor drop in the large battery cable to the starter.

The F terminal powers the field. Doing this ensures that the alternator still charges if the volt bulb burns out or that circuit goes open (your current issue).

As Dave mentioned the brown volt lamp wire goes nowhere near the ECM harness area. Goes from the fuse to the dash, through the bulb, back out of the dash and on to the C100 bulkhead connector (below brake booster). Out under the hood and on to the alternator.

RemoveBeforeFlight

 

[Tori]

I doubt you'll find anything associated with battery charging or alternator operations at the computer harness.

okay, good to know. What about all the other idiot lights that have stopped working ? Could those be associated with computer wiring ?

 

[hotairgnx548]

that on your

 

[hotairgnx548]

tori i say again where does the black wire with the yellow connector on the alt go to? john