Molex seems good - charging light still on

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stiffler4444
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Molex seems good - charging light still on

Post by stiffler4444 » Thu Jul 20, 2017 11:51 am

Hi all,

I know this subject has come up many times, but I'm having an issue that I can't seem to understand. I recently replaced my fan shroud mounting plate. Whilst off, I checked out my Molex (as I always had a faint charging light on, but no real charging issues) and found a couple of bad connections. I replaced the offensive spade connections and put everything back together. Now my alternator light is on bright and constant, but I'm having no charging issues. I run mostly short distance, but do stop / start the engine quite frequently, so I figured the batteries would have suffered low charge if there was an issue. I've been running like this for a few weeks now. I'm not incredibly savvy with electronics, but I did presume that if I had a bad connection that my batteries would eventually tell the tale. Any quick thoughts are of great assistance.

tx Dave
1972 710m

pinzinator
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Re: Molex seems good - charging light still on

Post by pinzinator » Thu Jul 20, 2017 9:44 pm

Bad diodes, bad grounds, loose belt. Pull the alternator and have it bench tested. Then check all connections and grounds. The regulator could be bad, or have a bad ground. The battery terminals could be loose or corroded. That's most of what could cause your electrical problem.
Last edited by pinzinator on Fri Jul 21, 2017 8:44 am, edited 1 time in total.

stiffler4444
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Re: Molex seems good - charging light still on

Post by stiffler4444 » Fri Jul 21, 2017 5:59 am

Thanks Pinzinator, I will have to pop her out again and see what's up.
1972 710m

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Jimm391730
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Re: Molex seems good - charging light still on

Post by Jimm391730 » Fri Jul 21, 2017 8:40 am

Having actual voltmeter measurements will tell a world of information beyond the "idiot light". What voltage are your batteries when at rest for an hour or two? (expect ~25V). What voltage do you get when the engine is cranking? (over 20V is good). What voltage do you get once the engine is running, preferably a bit higher than idle speed? (expect ~27-28V). All these should be measured at the battery terminal (not the battery clamp around the terminal). Let us know what you get.
Jim M.
712W and 710M

stiffler4444
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Re: Molex seems good - charging light still on

Post by stiffler4444 » Fri Jul 21, 2017 8:44 am

Jimm391730 wrote:Having actual voltmeter measurements will tell a world of information beyond the "idiot light". What voltage are your batteries when at rest for an hour or two? (expect ~25V). What voltage do you get when the engine is cranking? (over 20V is good). What voltage do you get once the engine is running, preferably a bit higher than idle speed? (expect ~27-28V). All these should be measured at the battery terminal (not the battery clamp around the terminal). Let us know what you get.
I was hoping you would chime in! I will perform these tests and report the findings.
1972 710m

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4x4Pinz
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Re: Molex seems good - charging light still on

Post by 4x4Pinz » Sun Jul 23, 2017 4:16 pm

Take a good look at the wiring under the front tin behind the alternator. We have seen many of the wires down to one or two strands left at the connectors to the alternator. Sounds like you have covered the main molex connector already but make sure the back side of the connector is in good shape, so many focus on the outboard side and let the inside go.

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pcolette
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Re: Molex seems good - charging light still on

Post by pcolette » Sun Jul 23, 2017 5:12 pm

4x4Pinz wrote:Take a good look at the wiring under the front tin behind the alternator. We have seen many of the wires down to one or two strands left at the connectors to the alternator. Sounds like you have covered the main molex connector already but make sure the back side of the connector is in good shape, so many focus on the outboard side and let the inside go.
Very good point! I've found problems there a couple of times. It's relatively inexpensive to replace that internal harness ($23) and is available from SAV (https://www.pinzgauer.com/showdetails.p ... 7121090090) and probably EI also. By replacing that harness you also get a new half of the molex connector. If it looks good except for 1 or 2 wires it's also easy to splice and repair the original if you prefer.
Paul C.
_________
'73 Swiss 710M
'89 Puch 230GE
2002 MB G500 (For Sale)

stiffler4444
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Re: Molex seems good - charging light still on

Post by stiffler4444 » Mon Jul 24, 2017 6:07 am

4x4Pinz wrote:Take a good look at the wiring under the front tin behind the alternator. We have seen many of the wires down to one or two strands left at the connectors to the alternator. Sounds like you have covered the main molex connector already but make sure the back side of the connector is in good shape, so many focus on the outboard side and let the inside go.
Yes, good observation. I did actually discover when I took, off the shroud, the alternator came with it and the smaller of the two wires broke right off. I replaced the connection and all is good now. We had a big pub crawl on Saturday so didn't get a chance to look at it. Sunday was a hangover day to say the least. :wink:
1972 710m

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audiocontr
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Re: Molex seems good - charging light still on

Post by audiocontr » Mon Jul 24, 2017 4:19 pm

Nice
1973 712m
(2) 1968 Haflingers 1 For Sale
1978 GMC Palm Beach
1979 Mini Ranger For Sale
1986 Corvette For Sale
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