Repair the Odometer/PRND321 LCD Display on a '99-'06 GM/Chevy Truck

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In this Instructable, I will show you how to repair odometer/gear select (PRND321) LCD on your GM truck. In this case, mine is a '02 Chevrolet Avalanche but this should apply to all GMT 800 series trucks within this age range.

A common fault on '99 - '02 GM trucks was the permanent or intermittent failing of the odometer/gear select LCD. This meant that you were unable to see what gear you were currently in, unable to determine the mileage of the vehicle, and unable to use the trip computer. The problem was caused by poor soldering of the internal components. Here's how to fix it…

Step 1: Determine the Fault

STOP!

Before starting anything, check that the "message center" is operational.

If both the odometer and message center are not working, the problem is likely to be a fuse (both of these displays share the same fuse.) The fuse in question is the IGN 0 fuse (responsible for "PRND321/odometer/VCM/PCM") which is located in the instrument panel fuse block on the driver's side edge of the dashboard (the edge which you can only access with the driver's door open.) Open it up, replace it, and see if that cures the problem.

If the message center display is operational, but the odometer display is not, read on…

Step 2: Obtain Access to the Instrument Cluster

First off, engage the emergency brake. You will be moving the column shift out of park, so this will prevent the truck from moving/rolling.

Insert the key into the ignition and turn to "ON" - you don't have to fire up the truck, but you will need to turn the key enough that you can move the gear stick down to the lowest position.

Using the steering wheel's height adjustment, move the steering wheel to the lowest position.

Finally, remove the dashboard surround. This simply pulls off, and requires no tools.

Step 3: Removing the Instrument Cluster

The instrument cluster is held in place by four (4) 7mm hex screws, one in each corner. Remove these.

Tilt the instrument cluster forward carefully, and unlatch the large wire harness on the back. The instrument panel can now be removed.

Step 4: Opening Up the Instrument Cluster

Remove the black panel on the back by loosening the clips.

You will now be looking at the back of the printed circuit board (PCB). Carefully pry the board away from the instrument cluster - it is held in place only by the pins of the stepper motors (labelled on the image)… but BEWARE, there is another small wire harness on the right and side of the board.

The last thing is to gain access to the back of the LCD panel. It is held in place by nine (9) pins and three white clips. Gently unhook the three clips, and bend back the display enough that you can get to the back of the LCD where the pins are connected. (See pictures to explain this step better)

Step 5: Soldering

Check the connections for the any dry joint - as you can see, the offender is the pin on the end in my case (apparently, it's usually this pin). Crack out the soldering iron and solder the joint securely. Try not to burn the plastic around the edges.

I'll hold off on the "after" picture because my soldering is embarrassingly poor! 

Step 6: Put It All Back Together

Bend the LCD display back carefully, ensuring that you have hooked in all three white clips.

Reconnect the small wire harness between the PCB and the instrument cluster.

Lining up the pins of the stepper motors with their corresponding sockets on the PCB, push the board back onto the instrument cluster. Put pressure on the back of where the stepper motors are (see photo).

Replace the back plastic cover of the instrument cluster, ensuring all clips are secured.

Step 7: Put It Back in the Truck

Connect the large wire harness on the back of the instrument cluster. Line up the instrument cluster and replace the four (4) hex screws.

Replace the dashboard surround - lining up the pins helps with this (see photo)

Step 8: Fire It Up!

Fire up the truck, and you should see the odometer/gear select (PRND321) LCD display working perfectly.

5 People Made This Project!

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43 Discussions

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daniel.malott.10

4 years ago on Step 5

Thank you so much for posting this!! Putting my 99 Silverado up for sale, would have been a hard sell when you can't see the mileage. This was a little out of my comfort zone and I am horrible with solder. Got it done and it was the pin you said it would be. Thanks again, saved my butt!

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W108

6 months ago

Tried to post this as a new instructable but that keeps crashing. So here it is as a reply post:

This is for 2002+ GM trucks that have a separate PRND321 display from the odometer display and it is very dim but the odometer message area is working just fine.

Step 1
For me this involved putting the car into the lowest gear so the lever was out of the way and pulling the cover off - there are no screws it jiust pulls off. Then remove the four 7mm bolts that hold the cluster on AND unclip the power cable from behind the cluster.

Step 2
Wear gloves! Do not get fingerprints on the gauge face.

Pretty simple at this point, just unclip at various points and the plastic front cover will come off as well as the back black cover. You will be left with exposed face gauge and needles and the circuit board on the back.

Step 3
The only thing holding the circuit board at this point are the gauge needles. They pull off by pulling straight up. Do NOT grab the needle as shown in the picture but rather the big black base. Take them all off and your circuit board will be exposed by taking the guage face off.

Step 4
When I tried to simply heat the resistors to reflow the factory solder the dumb 511 resistor came off so best just to solder over what is there. As you can see by my terrible job it does not need to be pretty to work.

Step 5
I plugged mine in to make sure I soldered what needed to be done to get it working. You might have to do all of them or only half like me. Since my soldering pen is huge i just did a few and it worked so I stopped while I was ahead.

Now is a good time to change any bulbs that are burnt out.

Put everything back together and do a happy dance. I now get to figure out how to fix my ride control.

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W108W108

Reply 6 months ago

More photos. Such a frustrating website. Especially on a phone.

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W108WilliamC137

Reply 6 months ago

I’ve added the “I Made This” for my 2003. It is different but still can be fixed easily.

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stormyra1

3 years ago

It is the illumination on the PRND123 you can't see the gear are in during the day but can at night. 2003 Silverado. headlights are on auto always but even if I shut them of during the day gears are still not visible. Tried the diming dial that's not it????? Help

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BowtieBoy_81stormyra1

Reply 3 years ago

I have a 2005 Silverado and when I cannot see the gears illuminated on the cluster I just push the odometer reading button on the cluster panel and it lights up the gear selector enough to be able to see what gear it is in

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EdgarC69

2 years ago

Hi, on my Tahoe the odometer is nice and bright but the PRND321 is only visible at night, do you think this is the same thing?

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guttersnipes199EdgarC69

Reply 2 years ago

I'm having the same problem on mt 2003 Chevy Avalanche. I'd like to know the issue as well.

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W108guttersnipes199

Reply 6 months ago

Not the same - you need to solder these resistors.

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BillP124

1 year ago

Thanks for the info. That pin of my 1999 was a dry joint also. For about a year I was able to get it to work by pressing several times on the trip reset. Guess that was moving the area where the led lead was and causing contact.

It works great since repaired. THANKS

It works great

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UncleEd

1 year ago

Great help for me! I downloaded and printed it, but wish I had printed it in color. It was, doubtless, the pin you said, though I soldered the next pin, too. I never accomplish anything in a "reasonable" amount of time, but it was just after lunch when I started and was still quite sunny, hot, and muggy long before supper when I finished. It worked on the first test and is still working.

You don't mention taking the battery cable loose. Far as I can tell, there is no fire hazard and no likelihood of shorting anything out. The hazard is your sanity and the warning "bell" that tells you the key is in the ignition with the door is open. Take the battery loose or disconnect the bell.

Another comment mentioned the pin/peg in addition to the three white clips holding the display. It's in Step 4, the last picture. You can see the three pins and a white peg next to the pin on the left. The clips were fairly easy, but it was a pain getting the display loose from the white peg. I wiggled and twisted it after I got the three clips loose and it took patience and tested my tranquility. Annoying to put back on, too. I'm not certain it would have caused a problem if I had broken or clipped it off, but I was careful and it's still there.

Thanks! It's 2017 now and the truck is a 1999. Wonder how long into the future this procedure will be done using these instructions..

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JerryS146

2 years ago

Where can I purchase the PRND321 LCD part for the 2002 1500 Avalanche?

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TomM311

2 years ago

EXACTLY the same pin on mine. Took about 35 minutes from start to finish to fix this issues. Thanks!

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NormanB23

2 years ago

great instructions that fixed my problem. Thanks!

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busterc

4 years ago on Step 8

This is very helpful but my 2002 1500 sierra has some of the same thongs that are on this post but my battery light stays on and I have no cruise control or tow haul and my blower motor stop all at the same time and the transmission can only be shifts manually.

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Sarah-Hbusterc

Reply 4 years ago

Busterc, did you ever find out what was going on with your Sierra? I am having the same problems with my 2002 Chevy Silverado 1500 - battery light stays on, mileage reader is out, gas and temp guages out, and I have no heater/fan/ac. I have replaced the battery, alternator and both tension pullies but no luck. It comes back with no issues when scanned. Any help is greatly apreciated.