Brake and seat belt alert lights

[Rweiss6]

The brake and seat belt alert lights stayed on too long before I got new battery, but seemed normal again w new battery.
Now they sometimes go on when I shift into reverse, then go off
Any ideas please? I found the relay 0218 under the dash, it seemed securely plugged. Could it be the relay is failing? Does that make any sense ?
It’s 82 Spider

[spider2081]

Power (battery voltage) is sent to one side of the lights when the ignition key is in the "start" or "run positions. The timer supplies the ground for the lights to light for approximately 5 seconds.
I think a visual inspection of the back up light switch wires is needed. Its not uncommon for the insulation to become oil soaked and fall off the wires causing intermittents. Possibly a short at the back-up light switch fools the timer into thinking the ignition was turned off and back on resetting the timer. Do the back-up lights work?
I would remove the timer from its socket and see what happens.
The back up lights and the timer are both powered from fuse 1 (closest to the steering column).

[Rweiss6]

Grabbed minute to check in driveway , back up lights do work , and for now those two lights did NOT go on , shifted into reverse bunch of times. However, the battery discharge light was on faintly, that’s a first. I bought a new battery month ago, old one wouldn’t hold charge.
When you said unplug the timer, do you mean the relay marked 0218 ? What should I look for ?
What does faint battery light indicate ? The fan belt is maybe two years old , doesn’t squeal
Electric issues not my specialty, but willing to learn and appreciate all advice.

[18Fiatsandcounting]

What does faint battery light indicate ?

On an '81 spider, it can mean that the alternator is overcharging the battery (less likely) or the alternator is undercharging the battery (more likely). Could be time for a new alternator.

But before running off to replace the alternator, one other possibility is simply that your idle speed is too low. If it drops too far below the 850 rpm spec, your alternator isn't putting out much at that speed so the battery charge light can come on dimly. Does the light go out if you rev the engine? If it does, I wouldn't worry about it unless you spend a lot of time idling with the headlights on.

If it's not an idle issue, make sure that the alternator connections are all clean and tight. There are shops that will test your alternator while in the car, some for free. Pick a reputable shop as there are shysters out there.

-Bryan

[Rweiss6]

I used multimeter to check battery -about 12.5 volts, then checked with engine running, it was 13.3 I think. So that’s good
I then screwed the relay tray back in, has 3 relays on tray, couple of larger ones loose, it’s pretty messy and loose, I finally got it secured, took ride all good
Then I tested battery and alternator again, numbers way lower , and had to jump it.
I must have loosened or disconnected something in or near the relay tray.
Can someone help me locate which relay or wires has affected the alternator ?
The wiring leading from and to alternator look quite clean and secure , it’s a Bosch with what seems voltage regulator on the outside ( small black rectangular box attached to it but not sure about that)
Thank you very much. This forum has been so helpful