Battery guage...Check light...

DeputyDipShizz · Jul 29, 2011

When I park my truck at idle with the AC on the battery guage drops and the check guage light comes on...If I turn the AC off...it goes right back up and the light goes off...and likewise when I start driving with the AC on...the guage goes up and light goes off...Battery or Alt problem? Maybe just check the connections at the terminals?

~TapaTalkAholic~

RamTech · Jul 29, 2011

Is the idle speed dropping and not coming back to it's previous RPM when you turn on the A/C?

DeputyDipShizz · Jul 29, 2011

Never noticed an idle drop or gain at all when using or not using AC

~TapaTalkAholic~

truckin151 · Jul 29, 2011

When your ac kicks on you are putting a load on the battery, I'd take it to one of the auto stores near you (Autozone/O-Reily/Checker/Napa) and have them do a load test. If it runs fine without the air on and drives fine without it on, then I'd put money on the alternator because it is pulling more of a load than the battery can keep up with. If it has a hard time turning over first thing in the morning I would put money on the battery because the cold crankning amps are not there. The battery should have a red blinking dot though if it was going out.

RamTech · Jul 29, 2011

That was my second thought. Alt could be on it's way out. You aren't using underdrive pulleys are you?

DeputyDipShizz · Jul 29, 2011

What the hell is an underdrive pulley haha...So no...I doubt it...Last time I got my oil changed they did the battery test and said it failed 2 of 4 but it was still "OK". I work at a battery mfg plant...we have an install area maybe I'll have em check it out and see what they think...I get a free battery every year so maybe its time

~TapaTalkAholic~

RamTech · Jul 29, 2011

Get your PCM scanned for any charging system codes. Low alternator output will set a code.

DeputyDipShizz · Jul 29, 2011

Would the SC3815 help me at all with that?

~TapaTalkAholic~

truckin151 · Jul 29, 2011

It should. Still though, you need to do a load test. Something is causing the battery to not stay charged when the ac is turned on which points to the alt. if it was the battery it wouldnt run right. These trucks do odd things when the battery is about to go.

If you get free batteries though, replace it and wait a few weeks and see if it does the samething.

Only other thing I can think of is that your power cable to the ac compresser has a damaged wire and everytime you send power through it its shorting out. BUt I cant recall if the ac compressor is always live or if there is only a current running through it when the truck is running and ac is turned on.

Out of all the issues to have, electrical issues are by far, IMO, the worst to diagnos and repair.

RamTech · Jul 29, 2011

Electrical is my specialty; I'd rather do that than anything. The compressor clutch is controlled on the high side and has a permanent ground. If there were a short in the wire, the TIPMCGW would set a code for it.

LB3711 · Jul 29, 2011

you get a dree battery and is the one you have original? Its near the end of life anyway. Start there. One question anything new done with your lights?

DeputyDipShizz · Jul 30, 2011

Yes free...and nope

~TapaTalkAholic~

LB3711 · Jul 30, 2011

just do the battery and start there

Battery guage...Check light...

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