1999 GMC SIERRA ATC FUSE CAUSING BATTERY DRAIN

SOURCE: Tail light problems on 1996 GMC Sierra pickup

I had similar problem with my 97 sierra... I only lost 1 light, then brake lights stayed on all the time... turns out the "t" connector for the trailer harness under rear bumper was rotted inside...unplugged the 2 parts of the harness and pluged them into each other with out the "T" harness.... everything works great... Hope it helps ya

SOURCE: 1998 GMC Sierra radio and display stays on all the time

First of all...does your truck have the retained accessory power (RAP)? If it does, the radio would always stay on with the key off until you open the drivers door. If it does have RAP and the door pin on the drivers door has went bad, then the truck doesn't know that you opened the door and continues to allow accessory power (although it would still cut off after about 20 minutes). If the interior lights come on when you open the door, then the pin is ok. If the lights come on, it could be the RAP relay. If it has gone bad, it is possible it is stuck supplying power and needs replacing. The relay should be labeled in the fuse panel, and there should be other relays in the panel with the same part number. You can swap a relay for the RAP relay and see if it fixes the problem...if it does fix it swap the relays back and replace the RAP relay. If the truck doesn't have RAP then it is possible the problem is in the radio..if you have a friend with a GM car or truck close to the same year you could swap radios and see if that fixes your problem...should be pretty simple. pull the cover off the dash, it just clips on, take out a couple screws that hold in the radio, unplug it and plug in the other radio. sorry so long winded...hope this helps you somewhat.

SOURCE: fuel pump fuse located on 1997 gmc sierra

The fuse is actually a Relay Switch and its located in the Fuse Relay Center on the driverside of the engine compartment. The Black Box is labled Fuse Relay Center, the diagram on the cap displays which Relay is the Fuel Pump relay...the Relay switch is usually $8-$15 depending on where you shop

SOURCE: trouble code

DTC P0420 Catalyst System Low Efficiency Bank 1

You will find a bad O2 Sensor behind the converter or a bad catalytic converter on the bank 1 side of the exhaust manifold. This is the one on the drivers side.

Colin Stickland

• 22516 Answers
• Posted on Apr 05, 2010

SOURCE: 2006 GMC sierra 1500 SL - Battery being drained,

only one major issue drains the battery and thats the diode pack in the alternator .