seeking advice on high voltage

Can someone offer advice on high voltage? I have a 740 (1990) that has a code pointing me to high or low voltage. I discovered this while trying to clear out a code for another issue. I checked the voltage at the battery with the engine running at idle and it was 14.4v. I believe that is high but not by much. Tried switching the regulator/brush pack (it was the original one that I put back in) and it brought the voltage to 14.3v with the engine running at idle.

I believe the battery is good as I measured 12.4v after it "rested" for a couple of hours.

Anyone care to comment on this? I am wondering about the diode bridge. I don't know what to expect if I have a bad diode in the diode pack. I tried to measure ac voltage and did not get much voltage at all, well under a volt.

thanks for the help

Reply to
newtovolvo
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The voltage will vary with temperature, dropping as the temperature rises.

14.3 or 14.4 is good for a cool day. Does your 740 have the temperature sensor plate under the battery that connects to the alternator?

Mike

Reply to
Michael Pardee

"Michael Pardee" wrote in news: snipped-for-privacy@sedona.net:

I am thinking of what other info I can pass along..... I don't recall seeing anything under the battery when it was changed in recent years, only a battery tray as I recall it was plastic. I must say I was not really looking very hard, as I was focused on changing the battery when I What size is this sensor plate in inches? This is a 1990 car, temp sensor sounds real sofisticated for a 90.

Air temp was around 50f maybe 60f yesterday when I made the measurements- I guess that could be a cool day?

Does this still seem normal?

Reply to
newtovolvo

"newtovolvo" skrev i meddelandet news:20050505080838.662$ snipped-for-privacy@news.newsreader.com...

My 740 -85 had a sensor under the battery. I guess this really never worked, the connections where cut by my Volvo shop.

A good idea is to measure the voltage for a longer period when driving the car. Voltage on my cars goes down to 13,7 or so after a while. I have made a cable set for the ciglighter connection and for a multimeter in the other end.

/aw (SE)

Reply to
Anders Wiklund

The one I have (85 760T) is the full size of the battery tray and has a cable coming out the back that plugs right into the alternator. If you didn't see that, yours must not have one.

The voltage sounds about right for the temperature.

Mike

Reply to
Michael Pardee

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