I need to buy a digital instrument gauge cluster for a 1991 chrysler newyorker fithavenue

digital part of dash ???? Instrument cluster , gauges etc.... Have the instrument cluster checked for DTC'S - diagnostic trouble code's , yes the instrument cluster an the BCM - body control module (GEM)
Is this what your instrument cluster looks like ?

Principles of Operation
The instrument cluster is a hybrid electronic instrument cluster (HEC). The instrument cluster gauges, warning indicators, and message center displays are either controlled and driven directly through hardwired circuitry, or the information is requested and received through the standard corporate protocol (SCP). The instrument cluster has self-test diagnostics capabilities using the diagnostic tool.

This is one guy's advice: Replace the speedo head, that should take care of the problem."

This site is also interesting because the guy said
General Motors cars had instrument cluster problems from 2003 through 2006. When I researched instrument cluster problems on the Internet what I found raised concerns in me. Many of those vehicles had problems that began with the instrument cluster, but eventually led to the engine refusing to start.
(an electronic instrument cluster, digital instrument panel or digital dash for short, is a set of instrumentation, including the speedometer, that is displayed with a digital readout rather than with the traditional analog gauges. Many refer to it simply as a digital speedometer.)

http://www.instructables.com/id/Erratic-Instrument-Panel-on-GM-Cars/

Chrysler PT Cruiser Dash Lights Instrument Cluster lights ...

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https://www.youtube.com/watch?v=Xl8B78vBDXk
Jul 8, 2015 - Uploaded by World Mechanics
Chrysler PT Cruiser Dash Lights Instrument Cluster lights ON & OFF Blinking COMMON PROBLEM! We took ...

PT Cruiser Dash Light/Instrument Cluster Removal and ...

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https://www.youtube.com/watch?v=rsITrfvYBIE
Jan 22, 2015 - Uploaded by WeekendHandymen
PT Cruiser Dash Light/Instrument Cluster Removal and Replacement ... Chrysler PT Cruiser Dash Lights ...

PT Cruiser dash lights replacement - YouTube

? 3:03
https://www.youtube.com/watch?v=S1dFuACAMk0
May 9, 2013 - Uploaded by 2stroketurbo
A quick overview of how to replace burned out dash lights on a 2005 ... How To Install Replace Engine Ignition ...

Need to have instrument cluster fixed or replaced ! How to Fix GM Speedometer Instrument Lighting Do you have a GM vehicle , Buick , Cadillac , Chevy , Oldsmobile , Pontiac , GMC ? Chrysler has cluster problems as well as Ford .

A mechanic would test the power and ground circuits at the cluster plug, but it may be tough to fix if you can't make the problem happen on demand.

Follow the link below.

http://www.bbbind.com/free_tsb.html

you need a haynes repair manual to locate instrument cluster screws to replace cluster bulb or replace cluster if digital..

The problem is your instrument cluster. Your type of vehicle is notorious for the instrument cluster failing. It will need replaced, or rebuilt.

Here you go. Under hood fuse block
Ign. Fuse E
and
ipc/dic
both fuses are 10 amp
I hope this helps. Take care.

well the issue is youe enitre gauge cluster i do understand that your speedometer is working but it is a cable speedometer not electronic like everything else in the gauge cluster so first i would recomend checking the voltage getting to your gauge cluster then just replace the guagecluster they are really cheap i a salvage and not hard to install at all but the cluster itself is not very comon to go out so make sure you check voltage to it first i wouldnt want you to go through buying and replaceing the cluster and that not fix it