NO VOLT LIGHT with key on

[usetaboost]

I've been battling this all week. Thought it was the alternator. Obviously it wasn't. I been googling my eyes out trying to find the info I need and come up short handed. All I get is mediocre diagrams and "the brown wire goes to the light. . Well the light has voltage on one side of the socket. Nothing at the alternator. Someone here that actually knows something could tell me in detail where this circuit all goes? Do our cars have a choke/heater relay this circuit passes through? I've checked all fuses, pulled the cluster and checked sockets and bulbs. Alternator is known good.

I'm sure this problem has existed the entire time I've had the car, just never had it running long enough to notice. BTW no dimming of headlights, car starts fine, can't find any broken or shorted wires. I need to get this fixed so I can get it in storage for the winter.

 

[Chuck Leeper]

"Well the light has voltage on one side of the socket. Nothing at the alternator".
+ at 1 side, then it's obviously not "making the trip" thru the bulb, OR the wire from the other side of the bulb to the alt is open. Could also be the socket.
Have you checked the bulb?
Caspers has the fix for the bad bulb syndrome...Once you get it corrected, I suggest you get 1.

 

[usetaboost]

I swapped it with the one above which is the only one that turns on asides from the see light. No change.

 

[b4black]

If you have voltage on one side of the socket, then the problem must be the other (ground) side? I have never needed to mess with that light but sometimes the switched side of things is the ground wire and the hot wire is always hot.

 

[usetaboost]

I assume it passes back through the bulkhead connector behind the dash. Where does it go from there? Fuse panel?

 

[RmvBfrFlght]

For an '83, goes like this:

From the GAUGES fuse (20A) via a PNK/BLK to the instrument panel.
Goes through the charge bulb
Exits the instrument panel via a BRN wire
Goes to C100 (bulk head connector behind fuse block)
Exits C100 in the engine compartment and goes to the alternator

At the instrument panel flex connector, pin 1 is from the gauges fuse. Pin 3 is where the charge bulb exits and goes on to the C100 connector.

RemoveBeforeFlight

 

[usetaboost]

Does the brown wire act as a ground for the light to work?

 

[RmvBfrFlght]

Does the brown wire act as a ground for the light to work?

Yes, at key-on, engine-off the alternator basically grounds the BRN wire to light up the bulb. You can do the same on the BRN wire to see where the break is. Ground it here and there and the bulb should light up. If you can get the bulkhead connector opened that will be helpful.

Of course it may be the instrument panel flex sheet that is the problem. Sometimes the traces open up, or the contacts become corroded.

RemoveBeforeFlight

 

[usetaboost]

I've checked continuity from the cluster bulkhead to the firewall connector. Checks good. Checked from firewall connector to brown wire on alternator, about 3 inches from connector. Checks good. Obviously I'm missing something, if it was a poisonous snake I'd be dead and half swallowed by it. Dumb question of the day. There's two red wires going to the back of the alternator. One from the positive from the battery and the other I assume is from the starter. The one from the starter has no power. Being's it's red, this should have power at all times even when disconnected from the back of the alternator, right?

 

[RmvBfrFlght]

I've checked continuity from the cluster bulkhead to the firewall connector. Checks good. Checked from firewall connector to brown wire on alternator, about 3 inches from connector. Checks good. Obviously I'm missing something, if it was a poisonous snake I'd be dead and half swallowed by it.

I would check the BRN wire at the alternator connector terminal. Unplug it from the alternator to access it. You can also ground that terminal and do a key-on, engine-off to check where the open is. Don't discount the dash flex panel and the connector to it. Even where the bulb is latched into the panel is problematic.

Dumb question of the day. There's two red wires going to the back of the alternator. One from the positive from the battery and the other I assume is from the starter. The one from the starter has no power. Being's it's red, this should have power at all times even when disconnected from the back of the alternator, right?

Fusible link at the starter could be open.

RemoveBeforeFlight

 

[usetaboost]

I'm pretty sure the cluster is bad. I have access to another so ill try swapping it either within the next few weeks or next spring.

 

[usetaboost]

Guess I'm gonna have to cheat it and put 12 volts keyed to the brown wire on the alternator. Is there any thing I can steal it from under the hood so I don't have to run a wire clear from the fuse block?

 

[ek02]

My memory is pretty bad, but if I am correct you can ground the brown wire at the alternator and the light on the dash should come on. If it does, the circuit in the alternator is bad. I'm not sure if yours has an internal voltage regulator, but that is the part that used to go bad all the time. The alternator would still charge OK, but no light. The other wire in the 2 wire connector comes from ignition and should be hot with the key on. You can hook a 12 volt test light clip to the battery positive post and touch the test light to the brown wire on the alternator and it should light up with the engine off, key on.

 

[usetaboost]

After all the crap I did, I figured while it was a part I'd spend an hour to mount the tach in the most pita spot I could find because I wanted it there. Ran all the wires and turned the key on. Guess what? Volt light turned on. Don't know if it's from the draw or something decided to work. Of course the rest of them don't work but at least the volt light does now. Thanks everyone for your responses. Now I can put everything back together, wipe down the car and wax it and install the radiator and fans.

 

[usetaboost]

BTW still have the cs alternator, 105 amp on the car. Battery has a solid 14.5 volts even with all electronics on. These alternators are everywhere and very easy to convert. You have to throw some a washer or two on the adjustment side to get them lined up but it's worth it if you plan on running electric fans or adding stereo equipment.