Carter0608

I have recently have had the gauges stop working on my 2003 Trailblazer while I'm driving except for my speedometer and tachometer. When this happens my dashboard lights come on(check gauges, abs, sest belt, and battery). To temporarily fix this issue I disconnect my negative battery terminal and all is well. Can someone please tell me what is causing this issue and what I can do to fix it.

chem_man

There are a couple of interior ground points that can become dirty and cause intermittent problems.


Both are located on the transmission hump just below the instrument panel, and they are both under the carpet. One is on the driver's side and is to the right of where your foot would rest on the accelerator pedal. The other grounding point is on the passenger side in essentially the same position. Clean them up really well, and then make sure the nut is tight.

Good Luck!

jfmorris

Have you checked engine codes after this happens? I ask because I've seen trouble codes that caused the vehicle to light up every light on the dash like a Christmas tree, to make sure you look and see the check engine light. You can reset the computer and trouble code temporarily by disconnecting the battery cable.

I would pull the codes next time, before resetting by disconnecting the battery cable. You don't want to be driving the vehicle if there is an underlying trouble code that requires repair.

chem_man

DO NOT DISCONNECT THE BATTERY - REMOVE THE APPROPRIATE FUSE(S). Why? Because when you reconnect the battery, the HVAC actuators inside of the dash are commanded to run a recalibration procedure which stresses the old brittle plastic gears inside the actuators and the brittle plastic gears break and leaves you unable to control where the air comes out, or control the temperature of the air, etc. Replacing at least one of them literally requires the removal of the entire dash! So, if you ever need to actually disconnect the battery, such as in the case of needing to install a new battery, be sure and use some kind of Keep Memory Alive (KAM) device to avoid the HVAC actuator recalibration routine.

KAM device usage: