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Electrical gremlins (Alternator not charging & pegged temperature read)
https://slantsix.org/forum/viewtopic.php?f=28&t=63707		 Page 1 of 1
Author:  Scooper [ Thu Jun 06, 2019 12:06 pm ]
Post subject:  Electrical gremlins (Alternator not charging & pegged temperature read)
Ok so, I've been trying to get my old 1966 Valiant going after it having been sitting a couple of years. Couple of days work, and she's running like a champ except for two issues:

1. The temperature gauge goes up to max when you start it. If you remove the connector from the sensor, the temperature bottoms back out to zero. It is not running hot. I have tried swapping the sensor for an identical one in a spare engine I have, and the same problem presents. Temp gauge pegs when key is on, goes to zero upon cut-off or wire removal. When the vehicle was last run two years ago, the temperature was reading correctly, now it is not.

2. Alternator is not charging. Replaced the alternator a few years ago, system stopped charging. Hadn't figured it out before I laid the car up. Now, got a new alternator again, and it is still not charging.

Here is the alternator I currently have: https://www.oreillyauto.com/detail/b/ultima-5353/charging---starting-16772/alternator-11425/f7cab2ae3cc0/ultima-55-amp-alternator-remanufactured/r111598b/4546522/1966/plymouth/valiant?q=Alternator&pos=0

I have both fields tied in. I took a test light to the battery stud on the back and have power. I saw in another forum where someone recommended another person (with success) to try grounding off one of the fields. I had no such success. I am THINKING that this one might be a bad regulator, but am uncertain.

Any input critical or otherwise would be a huge help here. I'm pretty mechanically aware of myself, but electrical has never been my strong suit.
Author:  Scooper [ Thu Jun 06, 2019 3:52 pm ]
Post subject:  Re: Electrical gremlins (Alternator not charging & pegged temperature read)
Update: snipped the wire going to the sender and placed a test light in-line. Pulsing as normal. WITH the test light in line, the temp gauge is functioning, if a bit on the low side, so I am assuming there is too much signal current going to the sender? My crappy multimeter set to 10v DC shows it floating between what appears to be 4.5v -> max (assuming 12v instead of 10).

Thoughts?
Author:  THOR [ Fri Jun 07, 2019 4:10 pm ]
Post subject:  Re: Electrical gremlins (Alternator not charging & pegged temperature read)
Scooper wrote:
Update: snipped the wire going to the sender and placed a test light in-line. Pulsing as normal. WITH the test light in line, the temp gauge is functioning, if a bit on the low side, so I am assuming there is too much signal current going to the sender? My crappy multimeter set to 10v DC shows it floating between what appears to be 4.5v -> max (assuming 12v instead of 10).

Thoughts?


Others may correct me, but my understanding is that the fuel and temp gauges are designed to run on somewhere near the 6 volt range. Of course with a mechanical regulator, that means you get the "pulse". Does your fuel gauge read properly? If you are using the old style single pin regulator with the dual pin alternator, this works just fine, but you only need to connect one of the field terminals; to my recollection, it does not matter which one. Hooking them both together will not work. I don't have the other pin grounded on mine, and it works great.

It sounds to me like you've got a regulator issue on the back of the cluster, and potentially a bad regulator on the firewall. SlantSixDan is selling some EXCELLENT replacements currently http://www.slantsix.org/forum/viewtopic.php?f=8&t=63543 for the firewall regulator. For info to replace the regulator on the cluster take a look at this: http://www.slantsix.org/articles/instrument-reg/instrument_reg.htm

~THOR~
Author:  Scooper [ Sat Jun 08, 2019 4:41 am ]
Post subject:  Re: Electrical gremlins (Alternator not charging & pegged temperature read)
Already have a new firewall regulator on the way. 99% sure that unit is bad. Fuel gauge appears to be operating as normal. Will check the cluster regulator if the firewall unit doesn't fix it.

Messing with the alternator fields does nothing. Unplugging, grounding, etc. No change in operation.
Author:  Scooper [ Sat Jun 08, 2019 5:30 pm ]
Post subject:  Re: Electrical gremlins (Alternator not charging & pegged temperature read)
Update: New firewall regulator arrived early. Fixed my charging issue! However it appears occam's razor doesn't apply here since my temperature gauge has not resolved itself. I suppose it's time for the cluster to come out.

Thanks for the help! Is there a way to reliably completely blow the old regulator in the cluster so the bypass will function unimpeded?
Author:  Scooper [ Mon Jun 10, 2019 7:54 am ]
Post subject:  Re: Electrical gremlins (Alternator not charging & pegged temperature read)
Update: cluster out, cleaned up etc. Actually is already the late-60's model board w/ the later voltage regulator, so I ordered a replacement for that as well.
Author:  THOR [ Mon Jun 10, 2019 11:12 am ]
Post subject:  Re: Electrical gremlins (Alternator not charging & pegged temperature read)
Sounds like progress.

Certainly seems likely that either the gauge is getting too much juice, or perhaps the gauge is shorted internally.

I'm fighting the opposite issue on my 63, where nothing works, even with the later regulator wired in per the link above.

~THOR~
Author:  Scooper [ Mon Jun 10, 2019 2:24 pm ]
Post subject:  Re: Electrical gremlins (Alternator not charging & pegged temperature read)
Well the strange thing is, as butchered as this car is, theres not a whole lot that doesn't actually work. Just a lot of pieces to put back together from the last guy.

Speaking of which, I discovered my *dead* blower motor is actually just not wired in. I traced the lead to a random rogue wire hanging near the main wiring harness under the hood. Unhooked. Don't have ye olde bat-tree in it atm though so not bothering to test it today.
Author:  Scooper [ Thu Jun 13, 2019 2:13 pm ]
Post subject:  Re: Electrical gremlins (Alternator not charging & pegged temperature read)
Update: Replaced cluster regulator with new VRC601 from oreillys. Also replaced the condensor. Now it is doing NEW things, hooray -_-.

Normal operation appears to be restored mostly. Temp and fuel gauges are operating, if a tad floaty.

****BUT****

NOW if I mess with the light switch, it sends those two gauges haywire. Pulling the knob out to turn on the lights, the gauges go dead. If I turn the knob to adjust cluster light brightness (lights on cluster aren't working either, yay), the readings for both gauges go up to max.

Am I missing something here?
Author:  THOR [ Mon Jun 17, 2019 12:14 pm ]
Post subject:  Re: Electrical gremlins (Alternator not charging & pegged temperature read)
Bad ground on the cluster from the sounds of it.

~THOR~
Author:  Scooper [ Tue Jun 18, 2019 10:52 pm ]
Post subject:  Re: Electrical gremlins (Alternator not charging & pegged temperature read)
Still having intermittent cluster gremlins. Going to try running a ground strap to the cluster tomorrow, thanks for the tip THOR I'll give it a shot.
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