C900 Instrument Cluster
Introduction


Oh boy...this is a fun one! You suddenly noticed that your odometer is no longer keeping track of your milage. How long has it been broken? Would that explain the sudden drop in gas milage? Why did I get pulled over for speeding when my speedometer said I was doing 65mph? What's that awful grinding sound coming from the dash? Welcome to the DIY instrument cluster replacement section. This is one of those jobs that you never want to deal with. Removing the instrument cluster is easy for the most part, but can cause a lot of frustration as the same time. Why? There are lots of things you can break behind that dash facia. Saab didn't make this piece of equipment simple to access. Unfortunately, I've had to do this job three times over the past 4 months due to mistakes and faulty equipment.

So I've learned a few tricks and now I pass them on to you...here we go.

Tools and other things you'll need:

Items you might discover you need once you get things apart:
914001091272c520ad3c1ae76fa680bf Let's get started!

C900 Instrument Cluster
Introduction


Oh boy...this is a fun one! You suddenly noticed that your odometer is no longer keeping track of your milage. How long has it been broken? Would that explain the sudden drop in gas milage? Why did I get pulled over for speeding when my speedometer said I was doing 65mph? What's that awful grinding sound coming from the dash? Welcome to the DIY instrument cluster replacement section. This is one of those jobs that you never want to deal with. Removing the instrument cluster is easy for the most part, but can cause a lot of frustration as the same time. Why? There are lots of things you can break behind that dash facia. Saab didn't make this piece of equipment simple to access. Unfortunately, I've had to do this job three times over the past 4 months due to mistakes and faulty equipment.

So I've learned a few tricks and now I pass them on to you...here we go.

Tools and other things you'll need:

Items you might discover you need once you get things apart:
914001091272c520ad3c1ae76fa680bf Let's get started!

C900 Instrument Cluster
Disassembly

The first stage of this project is removing the dash facia.

Stary by removing all of the buttons, switches, and devices that are installed in the facia.

Use your masking tape and pen to label the wiring harness for each button or switch you remove so that you can put it back together correctly later!

This also includes the Stereo... Be sure to write down your stereo settings so you can reconfigure it later.



label_buttons.jpg - 18930 Bytes

The next step is removing the four, long screws that hold the facia into the dash.

There are two on the left side of the steering wheel and two on the right.

TIP! - You can get to the far right facia screw by removing the ashtray plate rather than pulling the center console out.

Put the facia screws someplace safe and make sure you keep them in the correct order. Each screw is a different length although the middle screws look very close. If you really look close, each screw has markings on them to identify 1-4. They are little bands near the heads.

 

 

Once you have completed this, you must reach through the stereo slot and disconnect the following items. Your needle nosed pliers can help disconnect some of the connectors:
(Sorry there are no pictures, my camera doesn't fit!)

Remove the facia very carefully. It will resist as the heater control rod slides off the valve post and the vents come free from the airflow housing. Carefully slide the facia out from behind the steering wheel.


Hopefully, you don't have the same kind of mess that I do behind your dash!

Note the air vent vacuum hose harness and brass ring.


C900 Instrument Cluster
Disassembly

The first stage of this project is removing the dash facia.

Stary by removing all of the buttons, switches, and devices that are installed in the facia.

Use your masking tape and pen to label the wiring harness for each button or switch you remove so that you can put it back together correctly later!

This also includes the Stereo... Be sure to write down your stereo settings so you can reconfigure it later.



label_buttons.jpg - 18930 Bytes

The next step is removing the four, long screws that hold the facia into the dash.

There are two on the left side of the steering wheel and two on the right.

TIP! - You can get to the far right facia screw by removing the ashtray plate rather than pulling the center console out.

Put the facia screws someplace safe and make sure you keep them in the correct order. Each screw is a different length although the middle screws look very close. If you really look close, each screw has markings on them to identify 1-4. They are little bands near the heads.

 

 

Once you have completed this, you must reach through the stereo slot and disconnect the following items. Your needle nosed pliers can help disconnect some of the connectors:
(Sorry there are no pictures, my camera doesn't fit!)

Remove the facia very carefully. It will resist as the heater control rod slides off the valve post and the vents come free from the airflow housing. Carefully slide the facia out from behind the steering wheel.


Hopefully, you don't have the same kind of mess that I do behind your dash!

Note the air vent vacuum hose harness and brass ring.


C900 Instrument Cluster
Cluster Replacement

The second stage of this project is removing the instrument cluster.

Before pulling the cluster out, we need to disconnect it. Depending on the model year and included features of your car, you should have the following things to disconnect prior to pulling the cluster out.
ad44e52ccd0c65d46231ee8e0f07904f NOTE: This procedure is based on a 1989 900 Turbo. Your car's instrument cluster may have different connectors for the speedometer cable and cruise control speed sensor.

Because my camera is too large to get in behind the cluster, it is necessary to describe each of the above.

Remove the left speaker cover and disconnect the speaker (being careful not to lose the speaker wire.) If you look into the dash through the windshield from outside, you'll get a good idea of where everything is. Of course, if you're head is small enough to fit in there and see up close, then be my guest.

The Speedometer cable is an easy one. It is the black tube that goes into the back of the speedometer. The cable is held in place by a clip or latch that can be easily popped off. Pull the cable out of the speedometer where it will not be in the way.

The Cruise Control harness is also easy. If you're car has cruise, it will be a 3-pin connector which also attaches to the back of the speedometer. It is located to the left of the speedometer cable (if viewing the cluster from the back) and slides off with relative ease. With all wiring back here, use extra caution so as not to break or damage the wires.

This is the back of a 1989 speedometer. You can see the 3-pin connector for the cruise control speed sensor wiring.

Also, on this year's speedometer, the speedometer cable has a clip that snaps over the stalk on the back of the gauge.


This is the back of a 1983 speedometer. I believe that the angled circuit with the 2-pins is the older style speed sensor connection, but I cannot be sure.

On this year's speedometer, the speedometer cable snaps over the stalk on the back of the gauge and it held in place by the metal clip on the gauge stalk.

The second, threaded, fitting to the left of the speedometer cable stalk is the EXH box attach point. Disconnecting that box from the speedometer will prevent the EXH light (older models) from coming on again.


Instrument Cluster Harnesses...these bad boys can really be a pain. You must exercise extreme caution when removing these from the cluster. There are a lot of wires in these two harnesses and they are very cheap in construction. The harnesses are rectangular and go into the extreme left and extreme right sides in the back of the cluster housing. I recommend working them out of their sockets in a rocking motion, not pulling on the wires themselves. Pull the wires as a last resort!

When they come free, they sometimes bring the socket housing with them. The harness itself is white plastic, and the socket housing is black. So if you pull out a group of wires with a black harness, then you pulled too much. Not to worry, you haven't damaged anything.

Primary wiring harness socket with socket housing still attached (black connector)
Primary wiring harness socket with socket housing pulled free.
The cluster is held into the dash with four torx screws. There are two on the left and two on the right. Remove them and the cluster should be easy to free from the dash.

Remove the instrument cluster from the dash. If either socket housing came off with a wiring harness, remove it from the harness.

Now is also a good time to clean out the dust and dirt that has accumulated behind the dash over the years. It is also a good chance to inspect and replace the vacuum lines for cruise control, turbo gauge, and heating vent controls.

C900 Instrument Cluster
Cluster Replacement

The second stage of this project is removing the instrument cluster.

Before pulling the cluster out, we need to disconnect it. Depending on the model year and included features of your car, you should have the following things to disconnect prior to pulling the cluster out.
ad44e52ccd0c65d46231ee8e0f07904f NOTE: This procedure is based on a 1989 900 Turbo. Your car's instrument cluster may have different connectors for the speedometer cable and cruise control speed sensor.

Because my camera is too large to get in behind the cluster, it is necessary to describe each of the above.

Remove the left speaker cover and disconnect the speaker (being careful not to lose the speaker wire.) If you look into the dash through the windshield from outside, you'll get a good idea of where everything is. Of course, if you're head is small enough to fit in there and see up close, then be my guest.

The Speedometer cable is an easy one. It is the black tube that goes into the back of the speedometer. The cable is held in place by a clip or latch that can be easily popped off. Pull the cable out of the speedometer where it will not be in the way.

The Cruise Control harness is also easy. If you're car has cruise, it will be a 3-pin connector which also attaches to the back of the speedometer. It is located to the left of the speedometer cable (if viewing the cluster from the back) and slides off with relative ease. With all wiring back here, use extra caution so as not to break or damage the wires.

This is the back of a 1989 speedometer. You can see the 3-pin connector for the cruise control speed sensor wiring.

Also, on this year's speedometer, the speedometer cable has a clip that snaps over the stalk on the back of the gauge.


This is the back of a 1983 speedometer. I believe that the angled circuit with the 2-pins is the older style speed sensor connection, but I cannot be sure.

On this year's speedometer, the speedometer cable snaps over the stalk on the back of the gauge and it held in place by the metal clip on the gauge stalk.

The second, threaded, fitting to the left of the speedometer cable stalk is the EXH box attach point. Disconnecting that box from the speedometer will prevent the EXH light (older models) from coming on again.


Instrument Cluster Harnesses...these bad boys can really be a pain. You must exercise extreme caution when removing these from the cluster. There are a lot of wires in these two harnesses and they are very cheap in construction. The harnesses are rectangular and go into the extreme left and extreme right sides in the back of the cluster housing. I recommend working them out of their sockets in a rocking motion, not pulling on the wires themselves. Pull the wires as a last resort!

When they come free, they sometimes bring the socket housing with them. The harness itself is white plastic, and the socket housing is black. So if you pull out a group of wires with a black harness, then you pulled too much. Not to worry, you haven't damaged anything.

Primary wiring harness socket with socket housing still attached (black connector)
Primary wiring harness socket with socket housing pulled free.
The cluster is held into the dash with four torx screws. There are two on the left and two on the right. Remove them and the cluster should be easy to free from the dash.

Remove the instrument cluster from the dash. If either socket housing came off with a wiring harness, remove it from the harness.

Now is also a good time to clean out the dust and dirt that has accumulated behind the dash over the years. It is also a good chance to inspect and replace the vacuum lines for cruise control, turbo gauge, and heating vent controls.

C900 Instrument Cluster
Cluster Replacement

The third stage of this project is preparing the new instrument cluster for installation.

You've got the replacement cluster ready for installation. But is it 100% ready to go?

Most likely, you've gotten your hands on a used unit from eBay or a junkyard. It's a good idea to check it out before installing it...trust me.

Here are some things to check before installing the replacement cluster:

  • Speedometer Needle Spring

  • Odometer functionality

  • Light Bulbs

  • Tighten Ground Points For Temperature and Fuel Gauges

    • Speedometer Needle Spring - This spring is attached to the speedometer needle and is the spring that causes the needle to fall back to 0MPH when the car is not moving. This spring also keeps the needle from bouncing during normal operation. Some people instantly blame the speedometer cable for needle bounce, but this spring, if worn out, can also cause it.

    A good way to test this is to attach a drill to the speedometer where the cable attaches. Using a square-shaped screwdriver bit, you can drive the speedometer and cause the needle to climb as it would in the car.

    NOTE: You need to run the drill in reverse to cause the needle to climb.

    If the needle climbs smooth, then the spring is most likely in good shape. If not, you may want to find another speedometer, or have it serviced by a trained VDO service center. Attempting the replace the spring yourself is next to impossible.

    While your drill is attached to the speedometer, it is a good time to test the odometer. This is where my last cluster failed. A worn gear in the trip odometer was causing the whole thing to lose a mile for every twenty that I drove. Run the drill and watch to make sure the odometer is smooth and doesn't pause at all. Watch for the numbers to bounce and listen for any grinding noises. If you have any of these, get the odometer serviced, or find another one.

    Light bulbs - Now is the perfect time to test each of the bulbs and make sure they work before putting everything back together. Test each of the bulbs as shown below. If they don't light, then replace them with good bulbs from the old cluster.

    NOTE: The alternator idiot light needs to be a 3 watt bulb, because it's part of the charging circuit. The normal 1.2 or 2 watt bulb for the other idiot lights won't work.

    A 9-Volt battery held against the terminals of the smaller bulbs is a quick way to check if the bulb is still good.

    Use a piece of wire with the battery to test signal light bulbs.

    Many people notice that, as the car ages, the temperature and fuel gauge needles sometimes bounce while they're driving. Sometimes a loose wire on the sending unit, or even a failed sending unit can cause this. Most of the time, however, it is due to loose grounds on the back of the gauges themselves. Tightening the grounding points is best acheived with the instrument cluster out.

    The ground points for the temperature and fuel gauges are directly behind the gauges on the housing. Use a 7mm wrench or socket to tighten the nuts on these ground points.

    Do not overtighten the nuts as they can crack the plastic and render the gauge useless.

    C900 Instrument Cluster
    Cluster Replacement

    The third stage of this project is preparing the new instrument cluster for installation.

    You've got the replacement cluster ready for installation. But is it 100% ready to go?

    Most likely, you've gotten your hands on a used unit from eBay or a junkyard. It's a good idea to check it out before installing it...trust me.

    Here are some things to check before installing the replacement cluster:

  • Speedometer Needle Spring

  • Odometer functionality

  • Light Bulbs

  • Tighten Ground Points For Temperature and Fuel Gauges

    • Speedometer Needle Spring - This spring is attached to the speedometer needle and is the spring that causes the needle to fall back to 0MPH when the car is not moving. This spring also keeps the needle from bouncing during normal operation. Some people instantly blame the speedometer cable for needle bounce, but this spring, if worn out, can also cause it.

    A good way to test this is to attach a drill to the speedometer where the cable attaches. Using a square-shaped screwdriver bit, you can drive the speedometer and cause the needle to climb as it would in the car.

    NOTE: You need to run the drill in reverse to cause the needle to climb.

    If the needle climbs smooth, then the spring is most likely in good shape. If not, you may want to find another speedometer, or have it serviced by a trained VDO service center. Attempting the replace the spring yourself is next to impossible.

    While your drill is attached to the speedometer, it is a good time to test the odometer. This is where my last cluster failed. A worn gear in the trip odometer was causing the whole thing to lose a mile for every twenty that I drove. Run the drill and watch to make sure the odometer is smooth and doesn't pause at all. Watch for the numbers to bounce and listen for any grinding noises. If you have any of these, get the odometer serviced, or find another one.

    Light bulbs - Now is the perfect time to test each of the bulbs and make sure they work before putting everything back together. Test each of the bulbs as shown below. If they don't light, then replace them with good bulbs from the old cluster.

    NOTE: The alternator idiot light needs to be a 3 watt bulb, because it's part of the charging circuit. The normal 1.2 or 2 watt bulb for the other idiot lights won't work.

    A 9-Volt battery held against the terminals of the smaller bulbs is a quick way to check if the bulb is still good.

    Use a piece of wire with the battery to test signal light bulbs.

    Many people notice that, as the car ages, the temperature and fuel gauge needles sometimes bounce while they're driving. Sometimes a loose wire on the sending unit, or even a failed sending unit can cause this. Most of the time, however, it is due to loose grounds on the back of the gauges themselves. Tightening the grounding points is best acheived with the instrument cluster out.

    The ground points for the temperature and fuel gauges are directly behind the gauges on the housing. Use a 7mm wrench or socket to tighten the nuts on these ground points.

    Do not overtighten the nuts as they can crack the plastic and render the gauge useless.

    C900 Instrument Cluster
    Extra Items of Interest

    There is a blank bulb insert that is located next to the bulb for the low-fuel light. It is connected to the small single wire harness to the left of the speedometer.

    Please write me an email if you know what this connector/bulb is used for. Apparently, my car is not equiped with it.

    The dash light dimmer pot can be removed and cleaned with rubbing alcohol.

    Although I've never seen this go bad, there is no reason not to clean it if you can.

    Sometimes, the printed circuit for the tachometer will work itself loose.

    Make sure all six "wires" are in place and tight. You can test this by attaching the cluster to the wiring harness before tightening the cluster back into place.

    Use a can of compressed air to clean any dirt from the turbo gauge vacuum connector.

    C900 Instrument Cluster
    Extra Items of Interest

    There is a blank bulb insert that is located next to the bulb for the low-fuel light. It is connected to the small single wire harness to the left of the speedometer.

    Please write me an email if you know what this connector/bulb is used for. Apparently, my car is not equiped with it.

    The dash light dimmer pot can be removed and cleaned with rubbing alcohol.

    Although I've never seen this go bad, there is no reason not to clean it if you can.

    Sometimes, the printed circuit for the tachometer will work itself loose.

    Make sure all six "wires" are in place and tight. You can test this by attaching the cluster to the wiring harness before tightening the cluster back into place.

    Use a can of compressed air to clean any dirt from the turbo gauge vacuum connector.

    C900 Instrument Cluster
    Reassembly

    The final step of this job is re-installing the instrument cluster and dash facia.

    This is pretty straightforward and is a reverse of the removal process. If you can fully test the instrument cluster prior to tightening it into place, that is a good idea.

    Re-install the instrument cluster and reattach wiring harnesses and the speedometer cable.

    Before you re-install the dash facia, you may want to take the time to perform the following fix. The dimmer pot for the dash lights is located on the facia to the left of the steering wheel. Over time, this pot can break loose of the facia and spin in place. It is very difficult to remove this pot from the facia, but having it loose makes it nearly useless. I came up with a simple fix to prevent the entire knob from spinning in the facia. All you need are two short, thin, zip ties.

    Connect the two ties to one another, and then loop them through the corner of the dimmer pot. Then wrap them around the square button socket where the fog light switch is usually located.

    Use needle nosed pliers to tighten the zip ties so that they don't slide off the socket, and also prevent the pot from spinning. Done!

    If you are installing a different facia than the one you removed, make sure that all of the components are in place and that nothing is broken from the heat and air controls.

  • Re-connect all of the heater controls and hose harness before sliding the facia completely into place.
  • Then re-install the facia carefully. Take your time and don't force it.
  • Slowly feed all of the wiring harnesses into place and make sure all the dash bulbs are in their sockets.
  • Install the facia screws and tighten the facia down.
  • Then feed all your button harnesses into place, re-install the buttons and knobs.
  • Re-install the heater core valve rod, then install your stereo.

    • Congratualations! You're done!!!

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