Mazda CX-7 alternator high voltage

Asked by Jul 27, 2017 at 11:56 PM about the 2008 Mazda CX-7 Grand Touring

Question type: Maintenance & Repair

I have replaced battery and alternator and is still generating high voltage
getting higher as accelerating and boiling battery . Anyone know what voltage
should be on the 2 wires between alternator and pcm .? If engine at idle and
all power consumption is on( ac high beams, windshield wipers etc seems to
be just at about 15.5v but as I accelerate it goes up to 18v or more and
already burned the low beam lights. I had alternator tested and was good,
replaced it anyway and still the same.put new battery still the same.  I saw
others with this issue but none came back after they fixed it to confirm what
was wrong.  

1 Answer


the alt is getting a wrong signal , one big wire goes to the batt. for charging , one smaller wire is the voltage signal so it knows weather to charge or not , the other small wire is the exciter for the regulator , it needs an initial charge to work , a simpler system has 2 wires and gets voltage info from the batt. and wouldn't account for voltage drops from the rest of the system , it's o.k. for a hot rod ., your experience may differ

Your Answer

Mazda CX-7 Experts

  • #1
  • #2
  • #3
View All

Related Models For Sale

Used Mazda CX-9
5 Great Deals out of 356 listings starting at $4,795
Used Honda CR-V
42 Great Deals out of 2,400 listings starting at $990
Used Nissan Murano
64 Great Deals out of 1,149 listings starting at $1,399
Used Toyota RAV4
69 Great Deals out of 3,297 listings starting at $1,891
Used Nissan Rogue
51 Great Deals out of 3,176 listings starting at $2,919
Used Chevrolet Equinox
112 Great Deals out of 5,518 listings starting at $800
Used Mazda MAZDA6
18 Great Deals out of 576 listings starting at $950
Used Mazda MAZDA3
166 Great Deals out of 2,720 listings starting at $966
Used Ford Escape
175 Great Deals out of 5,430 listings starting at $995
Used Ford Edge
146 Great Deals out of 2,226 listings starting at $3,995
Used Hyundai Santa Fe
32 Great Deals out of 937 listings starting at $1,199
Used Jeep Grand Cherokee
117 Great Deals out of 3,469 listings starting at $2,999
Used Honda Accord
86 Great Deals out of 1,037 listings starting at $795

Used Cars For Sale

2009 Mazda CX-7 Grand Touring For Sale
4 listings starting at $6,490
2008 Mazda CX-7 Grand Touring For Sale
2 listings starting at $5,990

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.