240 1984 244 GL Dim/Intermittent battery light gremlin

1984 244 GL, b23f

Battery dash light keeps coming on very dim while I'm driving, pressing the brake seems to turn it off or attenuate the light. does not light all the time, having no issues with battery failure or power anywhere in the car. it comes on randomly while driving very dim and slowly climbs in brightness until I step on the brake (this is the only thing I've noticed has a direct effect on it. It never gets more than about 1/4 brightness and generally I don't notice it unless it's dark. Turning on AC, lights, other electronic devices doesn't seem to effect it noticeably when switched on.

brand new battery , new refurbished alternator (from trusted source), new alternator regulator assembly, fairly mint NOS engine wiring harness (no signs of crumbling or damage), just cleaned all engine grounds, yes my alternator ground is attached, fuses 13+14/fuse holders appear clean. I applied dielectric grease to a number of connectors in the engine bay when I replaced the engine harness, but I've since gone back and removed a great deal of it while trying to solve this issue thinking that it was introducing additional resistance to the circuits... no change. I am having no performance issues and it's been happening for almost two months now, dash light is only proof that something is odd.

borrowing a multimeter to take measurements in the next day or two, will update. last time I checked battery voltage was looking good. have not measured for drop between alternator and starter/+ battery lead yet. also have not removed cluster in a while to check the bulb, but I did reach up underneath and confirm the battery light connector lead is firmly attached.

I did notice that this issue arose sometime after I installed the new engine harness, however, the cabling looks pretty fresh and I've removed, inspected, and cleaned all the charging system related leads...

this is driving me nuts, suggestions?

thanks!

If you mean the battery light, your diodes are suspect in that alternator.

From just the other day.

http://forums.turbobricks.com/showthread.php?t=338100

I will update later with measurements from the battery and alternator output. hoping that if the diodes are damaged, it's just the dash light diodes... Kind of irritated because I just bought this alternator and don't really want to invest in new parts since it was advertised as "rebuilt." it was probably sitting on a shop shelf for a long time though, came from a defunct volvo shop that was liquidating stock so i'm fairly certain it was fully tested at the time it was rebuilt.

I did notice that the blower on my AC gets slightly stronger when I accelerate. is is normal for the light to get brighter as the alternator spins faster? seems like it'd be the opposite but I could be wrong, dash warning light is generally off when it's idling, even when loaded with all the electronics in the car on full blast.

Check 4 good grounds; dash connections, cracks in the circuit boards. I use DeOxyIt on all plugs/sockets.

I swear, the moment I post a problem on here that's been bugging me for weeks I solve it in 15 minutes.
borrowed a meter last night and battery measures 14.3V with car on, alternator voltage drop to battery + terminal is only .05v. grounds are measuring essentially 0v bleed. clearly my battery is charging fine and my alternator appears to be doing ok.

I'd already cleaned all the grounds in the engine bay, so I disconnected the battery - terminal and started tracing all my power connections out from the battery and alternator. turns out I'd been a little over zealous with the application of dielectric grease on some of my connections.

the + battery fuse holder red wire clips had a fair amount, as well as the exciter lead on the alternator. cleaned those and a few others off and drove the car around after dark running errands, idiot light is now off.

sooooo, let this serve as a reminder to all of those who apply dielectric grease to electrical connections... a little goes a long way, especially when you are applying a non-conductive insulator to an electrical connection. I cleaned and reset all connectors, and then reapplied a small amount of grease to the outside of the connector leads to seal them.

this was the last real concern I had for my vehicle going into winter, now feeling 100% ready to drive 800 miles next weekend!

9 months later update:
I found a fuse that was also causing voltage drop in the fuel system earlier in the year and my "professionally rebuilt" alternator died on me last month in the middle of vacation. I suspect the 55A alternator with all the GL model bells/whistles was being taxed pretty hard and an OEM 70A bosch seems to run things a lot smoother.