Alternator not charging - relay tray issue ??

[Rweiss6]

I lowered relay tray because brake light /seat belt delay light stayed on too long, it’s ok now , maybe relay 0218 was loose

Anyway, now alternator not charging, and red battery light NOT on. Problem seemed to start after I secured the tray, it’s pretty loose and messy, prob from previous owners efforts. My first time in there.

I tested battery with engine on and off , about 12.2 volts ( new battery !, but weakened now ) and w engine on - same reading, also w revving engine. However, before I secured the tray, voltage was in 13.3 or 13.4 range, so alternator was working.
What could I have loosened or disconnected ( don’t see anything loose, I don’t think) that could interrupt alternator ?
Appreciate all the knowledge and experience on this forum

[Rweiss6]

I meant to include it’s a nice red ‘81 Spider

[ORFORD2004]

Check your voltage at the alternator. When i bought mine, on my way home the car stall on me. The auto store said that the alternator was not charging enough. I remove the alternator and the guy who rebuilt it said everything was ok but he change the voltage regulator to be sure. At the end i think it was the ground of the battery on the body.

[Rweiss6]

Ok , just checked alternator output, at idle under 12v , but with a little gas , idle about 1500 goes over 13.4.
Problem began when I secured relay tray I believe , did I disconnect or loosen something ???

separate issue - I did finally and thankfully remove the door chime relay , # 0635 , Does anyone know if that affects anything else other than the chime ?

[gschwab]

Make sure that power is getting to the charge light and that the bulb is ok. I've heard of people replacing the charge light with an LED bulb and the alternator no longer charging. The current through the bulb is necessary for the alternator to work. Check the bulb and connections.

[Rweiss6]

Will do., def not LED , and it was working yesterday , but not now , even tho alternator is not working.
So maybe part of issue ???

Could the relay tray have something to do with the light ? I tightened brake/seat belt relay , removed chime relay ( just now, after problems began)
There is a missing relay in first slot , closest to seat , but it was missing already I’m sure

[Rweiss6]

Thank you again to this forum and to gent who said check the bulb , the post above this or just before that
Looks like when I replaced the relay tray it tugged on wiring that goes through the center console to the battery bulb, it was just a little loose at socket
I tightened it up, first tested battery voltage , then once running the voltage was in low 13s, so alternator was working again.
Very enlightening experience dealing w alternator, best part was removing the darn door chime relay.
Thanks again contributors. Love my Fiat !!!

[gschwab]

Glad you got it sorted out! Bad connections can be the source of all kinds of problems on these cars. They're generally well thought out, but sometimes the Italian we a little sloppy on execution...

[Rweiss6]

Uh oh. Celebrated too soon. Found the cause, but not the cure. Alt light not on when starting car , jiggled light socket, goes on but then may not. Does not light when car is running - so no warning- it’s clear when I key in, ready to start and only oil pressure light on

Guess have to trace wires and find weak spot May have to remove console ??? Such a tough small space to work in. Any ideas how to trace most welcome

[gschwab]

Do you have the wiring diagram? From what I could find, there is a connection from the ignition switch to fuse 2, then, from the same side of the fuse via a connector to the light. From the light, it goes through two connectors (one right behind the instrument) to the alternator.
I would trace in sections, wiggle the wires around, and see where the bad connection is. Good luck!

[spider2081]

Just a thought:
One of the differences between a generator an an alternator is, a generator has a permanent magnet and an alternator uses an electric magnet that needs to be excited in order for the alternator to begin to function.
For our spiders use the battery warning light circuit to excite the alternator. Any issue with the battery/alternator warning light circuit can cause alternator problems.
A simple test for an 81 Spider take 2 people. One operates the ignition switch while observing the bat/alt warning light. The other person removes the black/violet wire from the alternator and momentarily ground it. The warning light should light full bright when the violet/black wire is grounded and the ignition switch is in the "run" position.

[Rweiss6]

Need some help please
Sometimes the battery light on as normal when I start the car, when running multimeter shows 13.3 or so
After short drive, I turn off key, turn to on - no light. Start car, multimeter reads 12.3 ( so not charging)
Next day or so, light on, starts and charges , but not for long.
Then no light at all.
Could alternator be failing ?? I’ve jiggled wires like crazy, can’t get lights to go off when on, nor found loose wire/s
I had checked alternator by red wire on output of alternator and black on ground , week or so ago was 13:5 approx.
Tried today, seemed 12.4 or so. This was while light was not working
So is problem light circuit ??
Or is problem alternator , affecting the light ?
Any suggestions or advice.
Very much obliged.

[spider2081]

Engine not running ignition key in the "run" position.
I would try and measure the voltage at the violet/black wire attached to the back of the alternator just below the alternator output post. This wire controls the battery warning light in the tachometer.
With the wire connected to the alternator the meter should display something close to zero volts. When the wire is disconnected from the alternator it should measure close to battery voltage.
Momentarily grounding this wire should light the battery warning light while its grounded.

[Rweiss6]

Ok, new to me , want to get this right.
Key in run position, engine off, the battery light and oil light are always on , at least should be. Mine now sometimes off.

Multimeter to DC 20 , red lead on the wire, black to ground ? Test first attached, then loose. ?
If to ground , should light on tach Wouldn’t it already be on ?
Ill try to do tmrw…

[spider2081]

If to ground , should light on tach Wouldn’t it already be on ?

when the black/violet wire is disconnected from the alternator the light should not be lit. Power to the light is supplied from the ignition switch when the key is in the "run" or "start" positions Ground for the light is through the alternator. Disconnecting the wire from the alternator should turn the light off unless the wire is physically grounded.
I should have stated it this way. Disconnect the black/violet wire from the alternator. Turn the ignition switch to the "run" position.
Momentarily ground the black/violet wire. The battery warning light should be lit when the wire is grounded.
This tests the battery warning lights circuit.
If your battery warning light circuit is intermittent it could cause the alternator not charge the cars battery as the voltage from the light is used to excite the alternator into operation.