Instrument Cluster ODO and PRND... Blank, needles and other indicators ok

[Street]

Oh boy, another day, another Envoy Challenge!

So, 50mile ride south, no issues, stop to see my Mom for an hour or so after meeting a client, then head home. My folks driveway is heavily shaded by trees and buildings, so I'm used to the headlights coming on even with bright sunshine out (like today) - thus I didn't realize the Odometer and the PRND321 green displays where blank until I got back on the highway.

(edit) to be clear, the indicator lights and needle gauges work with no issues.

But there they are blank, dark, nada. So get home and pull the wiring diagrams for the IPC. Two fuses ( 24, 10A) and ( 22, 10A) look to be likely suspects. So they I check first - pulled, visual looks good, and DMM confirms good. And just to be sure I've got the right suspects, indeed pulling the fuses with ignition on does change the cluster, for instance #24 causes the power sweep tests and chime.

I've been over the diagrams for the last hour or more and I can't see any other connection to explain why all of a sudden both sections stop working.

Oh, and no codes stored, well, other then the P0420 that I'm working on. (got O2 sensors to try, then going for the big bucks of Cat, since I'd replace the sensors with a new Cat anyway).

2002 Envoy SLE 4wd - standard cluster (no DIC).

Of course, any help is always greatly appreciated from the fine folks at GMTNation. Anyone diagnosed a problem like this?


I'm so ready for a new Blazer EV RS. (sigh). Just trying to hang on till they ship next summer/fall.

 

[azswiss]

Had a similar problem on my '03 Suburban. Gauges and lights worked, just dim PRNDL & dim odometer which both then went completely dark. There are a series of resistors on the circuit board that have cracked solder joints. You will need to remove the display and open it up to get at these resistors.

A couple of videos to give you an overview of what's involved:

How to open up the cluster:
Envoy or Trailblazer Instrument Cluster Repair 2002-2009 :

Specific resistors to re-solder:
*AUTOMOTIVE FIX* 2005 Chevy Trailblazer gear selector and odometer light FIXED

P.S. Subsequently the compass & temperature indicator in the rear view mirror faded out then disappeared. Opened it up, re-soldered the resistors and now it works again.

 

[Street]

@azswiss Thanks for the quick reply. Probably a good time to get in there anyway, I think I'm down to 2 working backlight bulbs; maybe three.

Silly side question, the IPC is the record for the Odometer? not the PCM? And will it keep logging miles in this state? [I ask cause I'm not going to be able to get to the until at least Tuesday.]

Again, thanks for the video links, that is exactly the kind of help I needed.

 

[Blckshdw]

Silly side question, the IPC is the record for the Odometer? not the PCM?

Not silly at all, and yes, the cluster stores the memory for the odometer.

The same thing happened to me years ago, I ended up grabbing a DIC cluster from a junk yard, and upgrading with some momentary buttons, and eventually got the DIC steering wheel.

 

[azswiss]

Probably a good time to get in there anyway, I think I'm down to 2 working backlight bulbs; maybe three.

Had to replace those as well; pretty straightforward. Kits available online.

 

[Mooseman]

Or replace them with LEDs.

 

[Street]

Well, the good news is reflowing the solder on the board fixed the VFDs, and I replaced the backlights with these easy LED replacements (Amazon: White LED 12v 4.7mm). Just made them about 3mm off the board and bent the leads into L shapes, snipping off the extra - easy. 20m job. I did aim them slightly to avoid hot spots, I see just a bit on the speedo 10 o'clock and 2 o'clock positions - right where the LEDs are.

However, it seems that now my RPM stepper is wonky. I should have ordered them with the LEDs, but wasn't having any issues, until the shaft came out with the needle for the RPM gauge - dang it.

Next step, replace steppers, then replace bulbs to LEDs on the HVAC controls. There I think the only working light is the driver's side temp lever.

 

[Street]

Night photo - and yes, this is just about as dim as I can make them; I'm thinking I might need to put some dark film over the LEDs to tone it down just a bit. The picture is a bit washed out, the green dials are bright green and the red needles are as well. (and yes, the airbag system is complaining about the front impact sensor; not really interested in fixing a 20yo airbag - probably best if it didn't go off - and the SES is P0420; that's later this week.)

 

[Ilikemy3s]

Great looking dash.

 

[Mooseman]

Black electrical tape will fix that Airbag light real fast

I used a black marker on the LEDs in the steering wheel switches.

 

[Street]

Black electrical tape will fix that Airbag light real fast

I used a black marker on the LEDs in the steering wheel switches.

@Mooseman Thanks for the black marker tip -- that worked perfectly on toning down the brightness. I wouldn't have thought of that - too simple.

I did the marker trick while I was replacing all the stepper motors, went from X15s to X27s; I'm betting that the cluster is original from 2002 - so if I get 10 years out of the replacements - I'd call it good.