New Alternator not charging battery on 1989 240
#21
12-13-2016, 08:52 PM
Senior Member
the important dash light to watch for alternator issues is the battery/alternator light.... again, it should come ON when you turn on the ignition, and go OFF when the engine is running. sometimes it will stay on after starting the engine but go out when you blip the throttle, thats OK too, as long as it stays off.
the other lights come on when you turn the ignition on as a ligth test, to verify all the bulbs are good, they too should go out when the engine is running, except as needed to indicate things like OD disabled, or oil pressure low, or whatever.
the other lights come on when you turn the ignition on as a ligth test, to verify all the bulbs are good, they too should go out when the engine is running, except as needed to indicate things like OD disabled, or oil pressure low, or whatever.
#22
12-13-2016, 09:27 PM
Thank you very much for the explanation. It kinda makes sense now. Here's an update: I forgot to install all the screws on the rectifier. So reassembled everything and ran the tests. Battery voltage is 12.5. Same at terminal B. Terminal D has 12 v going in and when connected it's 9.3 v. And B to battery and alt ground to battery and battery to chassis ground are all under .01 volts. The car started up and at idle the battery was still showing 12.5. I revved it up and it got to 13.7 and held that. But here's where I'm going crazy again. Yesterday all my dash lights came on and stayed on with no charging. Now, only the check eng, oil and srs lights come on and they all go out after starting. So i did the grounding test with the wire to terminal D and they all came on. I have no idea what's going on. If there was a fuse blown in the instrument cluster they wouldn't have come on. Anything that pops up for you?
there's a regulator on the instrument panel circuit board, and a strip fuse. if either of those are bad, it gets sketchy. look at the first few messages in this thread, nichols explains it.
wait, what year/model car is this again? i think we hijacked a thread about a 1989 240.
#23
12-13-2016, 09:48 PM
Senior Member
all those things after you screwed down your regulator sound correct. sometimes you need to blip the throttle to get the alternator going. my BMW motorcycle is like that, and my 89 Jetta did that from new... if you start it without touching the gas, the alternator might not bootstrap til you blip it, THEN It starts charging.
there's a regulator on the instrument panel circuit board, and a strip fuse. if either of those are bad, it gets sketchy. look at the first few messages in this thread, nichols explains it.
wait, what year/model car is this again? i think we hijacked a thread about a 1989 240.
there's a regulator on the instrument panel circuit board, and a strip fuse. if either of those are bad, it gets sketchy. look at the first few messages in this thread, nichols explains it.
wait, what year/model car is this again? i think we hijacked a thread about a 1989 240.
#24
12-13-2016, 10:29 PM
what year 740? they changed instrument panels a couple times. the fuse is really a 'fusible link', and its soldered in place. it just looks like a jumper wire.
but, your charging problem si NOT in the instrument panel, if you read D+ = some middle voltage when the key is on, and the engine is off, with everything connected.
if you're not seeing charging voltage at the battery, whats the voltage at the big B+ terminal on the alternator, relative to the ground terminal on the alternator? if thats 13.6+ V and your battery isn't, then its a wiring problem.
but, your charging problem si NOT in the instrument panel, if you read D+ = some middle voltage when the key is on, and the engine is off, with everything connected.
if you're not seeing charging voltage at the battery, whats the voltage at the big B+ terminal on the alternator, relative to the ground terminal on the alternator? if thats 13.6+ V and your battery isn't, then its a wiring problem.
#25
12-13-2016, 10:47 PM
Senior Member
#26
12-13-2016, 11:23 PM
you can upload pictures as attachments, or put them on a photo website that allows linking, like I use smugmug, then link to the image. to upload an attachment, go advanced, then manage attachments, yada yada. keep the uploaded pictures around 800-1600 pixels wide (1-2 megapixels), don't upload native 28megapixel images.
#27
12-14-2016, 09:48 AM
Senior Member
#28
12-14-2016, 03:23 PM
#29
12-14-2016, 07:19 PM
Senior Member
I think I found where it should be but I've looked at 2 740 clusters and a 940 cluster and there's nothing there but those 2 holes. BTw, I picked up a working 100 amp at Pick n Pull and everything works as its suppose to. If anyone's in the same boat, a Bosch(that's what I got) will replace a Denso no problem. Later ones have a bigger B terminal bolt but the early ones are the same and fit right in, no modifying. Thanks again for your help.
#30
12-14-2016, 08:15 PM
the fuse is the thin section of circuit between those two copper rings, as outlined by the dotted lines. it does not look blown.
the other important bit on the instrument panel is the voltage regulator. but wait, I'm not seeing one on a 1991 740/940 panel, so maybe thats just a 240 thing??
the other important bit on the instrument panel is the voltage regulator. but wait, I'm not seeing one on a 1991 740/940 panel, so maybe thats just a 240 thing??
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Volvo 240, 740 & 940
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