I am experiencing a charging issue with the engine battery on a 1976 GMC Palm Beach Motorhome. I had the engine battery to go dead while going down
the highway. I took the alternator off and took it to NAPA parts store for a bench test and was told the alternator was "dead"! I replaced with a
remanufacture alternator. After doing so, I started the engine and the "GEN" light came on. I turned the ignition off and waited a couple of minutes
an re-started the engine. After re-starting, the "GEN" went off, but it still did not appear to be charging. I checked the battery and am showing 12
volts. I checked the "red" wire to the alternator prior to starting the engine again and I do not have any power. I started the engine and am still
not getting and voltage reading on the red wire to the alternator.
The "yellow" wire coming from the alternator plug is showing 12 volts when I check it against the brown wire next to the yellow wire in the plug.
I have traced the red, yellow, and brown to the from of the hood area looking for an in-line fuse link or a voltage regulator box (Nothing found). All
three wires run to the hood area and after doing so, the red wire is piggy-backed with another red wire running to a blue box {mounted on the back
wall with GMC 706751 labeled) with one red wire going to a solenoid. The yellow wire coming from alternator runs to the hood area and is pig-tailed
with a red wire, which the red wire goes to one of the three post on top of the blue GMC 706751 box.
I did discover today, when I turn the house battery on, the red wire on the alternator is reading 12 volts. Turn house battery off and turn engine
battery on, no voltage reading on the red wire at alternator.
I am trying to find out of the blue GMC box is the problem or would it be a bad solenoid? I have attached a couple of pictures of the blue box and the
solenoid.
Any assistance will be greatly appreciated.
Samuel Ferguson
the highway. I took the alternator off and took it to NAPA parts store for a bench test and was told the alternator was "dead"! I replaced with a
remanufacture alternator. After doing so, I started the engine and the "GEN" light came on. I turned the ignition off and waited a couple of minutes
an re-started the engine. After re-starting, the "GEN" went off, but it still did not appear to be charging. I checked the battery and am showing 12
volts. I checked the "red" wire to the alternator prior to starting the engine again and I do not have any power. I started the engine and am still
not getting and voltage reading on the red wire to the alternator.
The "yellow" wire coming from the alternator plug is showing 12 volts when I check it against the brown wire next to the yellow wire in the plug.
I have traced the red, yellow, and brown to the from of the hood area looking for an in-line fuse link or a voltage regulator box (Nothing found). All
three wires run to the hood area and after doing so, the red wire is piggy-backed with another red wire running to a blue box {mounted on the back
wall with GMC 706751 labeled) with one red wire going to a solenoid. The yellow wire coming from alternator runs to the hood area and is pig-tailed
with a red wire, which the red wire goes to one of the three post on top of the blue GMC 706751 box.
I did discover today, when I turn the house battery on, the red wire on the alternator is reading 12 volts. Turn house battery off and turn engine
battery on, no voltage reading on the red wire at alternator.
I am trying to find out of the blue GMC box is the problem or would it be a bad solenoid? I have attached a couple of pictures of the blue box and the
solenoid.
Any assistance will be greatly appreciated.
Samuel Ferguson
