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Charging Trouble

Q

QisofrKuin

Member
Joined
Feb 19, 2021
Location
Dallas, TX
Hello all,

I have been scouring the many bits of info about various charging issues but haven't found one matching my issue yet, so thought I'd put this out.
My '81 244 DL is not charging the battery, but the battery indicator light is not coming on. This is not the only thing on the dash that doesn't work--neither the clock, nor temperature gauges work, and when I turn the key to the "on" position only the parking brake light comes on. This was not the case when I bought the car a few months ago, at which point the lambda-sond light would also come on, and the clock worked (not the temperature gauge though). The gas gauge, parking brake light, and overdrive light all still to work.
Now, my question is whether some bad connection to the dash could be preventing the alternator from charging the battery, as I seem to have read that the circuit passes through the warning light. I have checked the fuses and the grounds and they all seem good. I looked at the alternator brushes and they seemed plenty long with good, smooth surfaces. I'm worried that I'll buy a new alternator and not have it fix the problem, so any advice is welcome

Thanks
 
99% faulty solder joints at the back of the instrument. This problem is not toooo unusual and sounds like it if random warning lights do not come on.
Even if you do not notice visually broken solder joints, they can go bad.

I had the same issue on my 940, reflowed a few joints and all lights lit back up.
https://forums.turbobricks.com/showthread.php?t=350999
 
Have you tested the warning light circuit? You do that by grounding the wire to the alternator case. Then turn the key on. If the light comes on the circuit is ok and the fault lies in the alternator. Using the case of the alternator checks that ground at the same time. If the light doesn't come on. Ground the wire to the valve cover or another good ground. If the light works then. The warning light circuit is ok and you need to check the alternator ground wire.

If the light never comes on. then you have either a bad bulb or something going on with the circuit board in the cluster as Fa182 suggested. The clock and the gauges not working can be the circuit board cracks he mentioned. Another issue that happens is failure of the 10v voltage regulator for the temp and gas gauge.

Seems from your description the fuse for the instruments should be checked as that provides the power for the gauges. The clock gets a constant power feed. Since you are missing that you definitely need to check/replace fuses.
 
I can't believe his searches didn't come up with the little red alternator wire! Also, that the wire may be broken or the alternator ground strap. Same year and model as mine.
 
johfraser said:
I can't believe his searches didn't come up with the little red alternator wire! Also, that the wire may be broken or the alternator ground strap. Same year and model as mine.
Click to expand...

By the 'little red wire' do you mean the ground wire? I've tried taking mine off, cleaning it, and re-tightening it with no luck. There was also a larger red wire that appeared to be a ground that had broken off at the tip that ran down underneath the alternator to the bottom of the engine block, so I crimped a new connector and grounded at the bolt that holds the bracket for the silver engine hose, whatever that thing is I cannot remember its name at the moment. I'm planning on doing the tests Dave suggested after work tonight and see if that can't tell me something. Thanks everyone for the suggestions!
 
There are three wires on the alternator. The small red is the warning light as mentioned. The large red is direct to the starter and the battery with out a fuse! Make sure that is never grounded as it's hot all the time and can burn your car down. The ground wire is usually blue if it's original. The main thing is to make sure the case is grounded with a wire to the alternator bracket on the block.
 
See my posting of Charging Circuit at:
https://volvoforums.com/forum/volvo-240-740-940-12/battery-drain-1990-240-a-107006/

Your alternator, like mine, may be upgraded to an internal voltage regulator in the brush assembly. If so you can ignore parts A and G. The small red wire connects to the warning light and plugs into the alternator with a flat ?? blade terminal. The large red wire from the alternator?s output terminal goes to the battery via the starter. There is no fuse so disconnect the battery ground when handling it. The alternator ground is just below the letter D. It connects the alternator case to the engine block and is the same size or larger as the large red wire since it carries the same current.
 
dl242gt said:
Have you tested the warning light circuit? You do that by grounding the wire to the alternator case. Then turn the key on. If the light comes on the circuit is ok and the fault lies in the alternator. Using the case of the alternator checks that ground at the same time. If the light doesn't come on. Ground the wire to the valve cover or another good ground. If the light works then. The warning light circuit is ok and you need to check the alternator ground wire.

If the light never comes on. then you have either a bad bulb or something going on with the circuit board in the cluster as Fa182 suggested. The clock and the gauges not working can be the circuit board cracks he mentioned. Another issue that happens is failure of the 10v voltage regulator for the temp and gas gauge.

Seems from your description the fuse for the instruments should be checked as that provides the power for the gauges. The clock gets a constant power feed. Since you are missing that you definitely need to check/replace fuses.
Click to expand...


This is all proving very educational. So far it appears that I had a bunch of problems all at once. First, the ground for the alternator had sheered clean off, which I had then improperly grounded to the frame rather than the alternator. I fixed that, then tried the key, no change. So I tried grounding my warning light wire to the alternator case, turned the key to 'on' and I had all my lights back. Wonderful! So that means, if I understand correctly, my alternator is no good. I have a new one to put in so I guess that's the next step, since it appears everything else is in good shape. Tried changing my clock fuse, no luck. So probably need to check the board, and since my fuel gauge works but my temp gauge doesn't maybe I'll find the fix for that as well. One final question. The first time the car died on me was while I was driving in the rain. Is it possible water could've found an exposed wire and killed the alternator? Or is just as likely that the alternator was about to die regardless of the rain? I ask only so that I can avoid killing another alternator if anyone does in fact think the rain may have done it. Thanks everyone for all the advice.
 
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Slight turn of events, but perhaps not important. I decided to try to give her a start despite the warning lights still being off. I knew her battery was almost totally dead from a previous test, but she managed to barely turn over. I ran her for just a minute, but as I turned her off I noticed the battery light flash on. So I turn the key back to the 'on' position and what do you know, all my lights are back. I tried running her for about 10 minutes with the lights on, and no problems. Is it possible the battery just didn't have enough juice to pull the lights up? The would seem surprising to me, but I guess I don't know for certain. Any thoughts?
 
Do you have an external voltage regulator on your alternator?

The '81 greenbook drawings (TP30316 from ozvolvo.org/archive) show it mounted by the passenger fender next to the radiator overflow tank, but I think they changed to an internal voltage regulator in the very early 80s, and many have been upgraded. If you do, the dashboard alternator wire gets grounded through the external regulator. If its connections are poor, it might explain your problems (other than the broken alternator ground wire), and rain might cause the connections to be worse.
 
My issues unfortunately have not yet been entirely solved. Often when I put the key in the on position for the first time, my dash lights will not come on. But if I start the car, run it just for a moment, then turn it off, all my lights are back. Odd. I've taken a volt meter and when reading between the neg. terminal on the battery and the alternator case I get -.05, when reading to the engine block I get -.01. Does this difference mean I have a problem somewhere between the block and the battery? Or is it most likely I just need to address those solder joints?
 
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