Repair 7

How to Disconnect a Battery to Fix Idle On a Duramax

General Motors uses a Duramax diesel engine in some of their full-size trucks. Normally, a Duramax idles between 500 and 1000 RPMs when the engine is cold, but with a warm engine the RPMs typically reach around 2000. If you need to fix your idle speed, its important to disconnect the battery first to keep you from getting shocked while you work. Unlike most vehicles, the Duramax engine has two batteries instead of one. However, since they are hard-wired together -- running parallel -- you only disconnect the one closest to the engine. Overall its a simple process and only takes a few minutes.

Instructions

1

Pull the hood release lever under the drivers side of the dashboard. Open and secure the hood of the truck. Then, locate the batteries. Youll notice two batteries sitting to the right of the engine, but only the battery closest to the engine connects to it. This is the one that needs to be disconnected.

2

Use a flathead screwdriver to pry off the black cover on the negative battery terminal. Using a wrench, loosen the nut attached to the clamp. Then, pull the negative battery cable from the post. Set it to the side where it wont touch anything metal.

3

Using a flathead screwdriver, take the red cover off the positive battery terminal. Use a wrench to loosen the nut that holds the clamp in place. Then, pull the positive battery cable from the post. Put it to the side and make sure it wont come in contact with anything metal.