Question about 2003 GMC Sierra 1500

1 Answer

I have a gmc 2003 z71 with codes 1637&1638 battery not charing alt is ok? Need help. Battery is new checks out good. Truck battery drains with in 5 mins truck stops running. Tech checked the truck he says it could be computer, cluster package. Replaced cluster 3 times all ready

Posted by on

  • Jeffrey Turcotte
    Jeffrey Turcotte Oct 06, 2010

    do you have a voltmeter in the panel, and, if so, what does it read with the engine running?

    Why replacing cluster--instrument cluster?

    Have you checked for a short?

  • redboat1359 Oct 06, 2010

    Yes, it reads about 10 volts then falls, when I charged the battery it read norm, then plus 14 volts



1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 20 achievements.


    An expert that got 10 achievements.


    An expert that got 5 achievements.

  • GMC Master
  • 8,734 Answers

OK, I'd say you have a short, and a big one at that. Can you troubleshoot circuits? If yes, start at the engine compartment relay box and start checking fuses and any fusible links or circuit breakers in there.

Please see my tip at . These are generic instructions. If you get stuck or need specific instructions for your car, please get back to me with model, year and engine info.

If you find a bad circuit, I can pull your wiring diagrams and tell you where to look for the short. Please remind me what the z71 means--this is a Sierra, right? Do you have dual batteries?

Posted on Oct 06, 2010

Testimonial: "Thank you for your time. In this day and time it is to hard to find a person like your self..... Thank very much......"


1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya Mechanic can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repair professionals here in the US.
click here to Talk to a Mechanic (only for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017


Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Battery light stays on. Guage cluster amp meter reads normal charging 13-14 amps. Truck starts normal.

If charging light is on, it means some thing in the charging system is going bad. use a test light!-- battery voltage at battery when truck is off should be at least 12.6 or better, if alternator was charging good. if less than 12.4 and it is charging ok. battery is going bad. when engine is running, at the battery there should be at least 13.8 to 14.2 volts or better.if alternator is ok, all checks are done at the battery posts to determine voltage. Hope this helps you out! if less than 13.8 or lower while running. alt, is bad.

Jul 15, 2014 | 1989 Ford F 250

1 Answer

Opel Corsa Sail 1.6 (2003-2005)- Alternator does not charge the battery in spite of rectifying the relay cut out unit twice, the 'negative' battery terminals overheat and drains the battery. On start-up...

sounds like a bad earth to the body of the car or try the engine earth best way to check for a bad earth is get a jump lead and put it from your negative post on your battery and attach the other end to a good earth on the engine and see if the problem goes away

Nov 19, 2013 | GMC Dura Cars & Trucks

2 Answers

Battery keep draining down

Make sure that there are no lights or components running in your vehicle when it is shut off. If your battery is loosing power when it is off then it is a shot battery and you need a new one. if the battery is going dead when you drive then you have a bad alternator. good luck

Feb 05, 2011 | 2000 GMC Denali

1 Answer

Changed a bad alternator, new alternator woeks but won't always charge. VM says it's charging and good, so does Autozonw machine but the battery icon keeps flashing. Really stumpped. 2004 Ford Truck...

check your battery make sure it is able to take a charge. ,if the amps are good check your connection, from altenantor to battery. check voltage drops, battery drains. Your problem most likley seems to be
your battery. Your starter might also be draining your battery. You ll find the problem keep looking.

Apr 25, 2010 | 2003 Ford Escape

1 Answer

Stopped while running. alt bench tests ok,

you need your fuel filter most cars and trucks will only run a short time being bypassed because of the wiring

Oct 15, 2009 | 2000 GMC New Sierra 1500

3 Answers

Lights keep flickering and battery light blinking on and off. bought new battery. problem still there

Check any plugs you have for hooking up trailer lights. Sounds like you may have a short. I had a similar problem in a '93 Z71 and it was the plug for trailer lights. If thats ok, check that the main ground wire to the battery is secured tightly to the truck. In an 80's Scottsdale that wire had corroded at the truck end and alsp caused a similar problem.

Sep 14, 2009 | 1996 GMC Sierra

2 Answers

RFA battery low. What does this mean

Check you Key FOB for a low battery.

May 20, 2009 | 2003 GMC Sierra 2500HD

Not finding what you are looking for?
Cars & Trucks Logo

181 people viewed this question

Ask a Question

Usually answered in minutes!

Top GMC Experts


Level 3 Expert

77169 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22265 Answers

Ronny Bennett Sr.
Ronny Bennett Sr.

Level 3 Expert

6927 Answers

Are you a GMC Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides