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Hello guys

This is my very first post on this forum hoping to get help.

I got this 1995 saab 9000 CSE a while ago and everything thing is fine except the cluster information display which shows the MPG and miles to empty tank and gears and volt meter.
It works fine but it gets very very dim to a point that I cant see anything ant it turns off completely.
it happens while driving no matter light or dark. It gets full bight then dim then gone and it does it again. Not very fast like every 20 minutes or so.
and sometimes it just work for hours. and The interesting thing is that clock is not affected by this. it is always bright.
please help me out if you have any information regarding this.

Thank You
 

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Mine does this too. I haven't tried to fix it yet, but the 'daylight sensor' (which automatically dims the display items you mention) is in the clock (small red dot on the face of the clock). I picked up a replacement clock from the junkyard and I'll plug it in today to see if it fixes the problem.
 

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Sorry about the format. I had to convert a word doc to pdf, extract the pdf pages individually and then convert the pdf's to jpgs. They are legible when opened.

Shine a flashlight right up close to the light sensor in the lower left corner of the SCC. Note whether the SCC display and the dash display increase noticeably in brightness.

If the SCC display responds but the dash display does not (or is erratic) one of the connectors (the 8 pin or 3 pin IDK which one) in back of the SCC probably needs to be wiggled and pushed in. One of those 11 wires supplies power over to the dash lighting from the SCC.

Note number 5 in the fault finding list: Check that the contact surfaces of the connectors are undamaged and clean. This is important as the currents involved are weak.
 

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I think - that they're talking about just the LED intensity of the computer (EDU) info display that is controlled by the SCC - not the cluster illumination (i.e backlighting).

The data from the computer is displayed in the lowest part of the instrument cluster - right in the middle - and is displayed by the use of LED's. It shows outside air temp, system voltage, mpg, etc. The intensity of that lighting is controlled by the previously mentioned light sensor on the SCC

If you are having problems with the backlighting, rather than the LED display for the EDU, that is controlled by the interior lighting rheostat on the dashboard.

There are 7 lamps in the cluster that repined to that rheostat - 4 for general lighting and 3 for the EDU display:




As shown in the above image the EDU backlighting consists of 3 lamps. Here is the procedure for changing them:



Special Thanks to Tom Townsend for this information!​

SAAB 9000 EDU BULB REPLACEMENT

First you'll need a 20 torx driver, a 10 torx driver, or possibly a Phillips screwdriver, depending on the year of the car, a 8 mm socket or wrench and a 25 torx driver.​

Pop off the trim pieces on each A-pillar, by the windshield. They are held by three clips that just pop out when you pull back on the panel. Then remove the three screws holding the speaker grills on each side. Be careful if they have LEDs or solar sensor installed in them. If you go back down the LEDs length, you can unplug them at a connector. Make sure you position the wiring so you won't forget it on reassembly or lose it down in the dash. Remove the rubbery speaker insulation.​




Now remove the two screws on each side as well as the 8 mm bolt holding the dash top down. On the side above the glove box, open the glove box and remove the rubber plug along its upper side. There is a screw behind that plug. Remove it. On newer 9000's there is one more screw about 2/3 of the way across the instrument cluster going upward into the dashpot. Find and remove it if the dash top seems to still be held there. After the screws are out, raise the front of the dash top and pull it toward you. Some have a cable that needs to be installed in a clip, all have a clip at the rear center that must be pulled in and out of. Carefully remove the dashpot from the car, it has sharp edges that may cut seats, dash etc. Newer cars have the solar sensor in the center of the dash, reach in and disconnect its wiring.​

There are two screws at the upper corners of the instrument cluster. They come in from the back. The bottom of the cluster is held by two feet with rubber boots on them. Picking up the cluster often causes these feet to fall off. I find them and use a bit of glue to hold them to the cluster. If they aren't reinstalled, the cluster will fit loosely and rattle, vibrate. If the feet are lost, you can slit a piece of vacuum line and use it in their place or PlayDoh or dum will work too.​

With the key off, carefully unplug the electrical connectors. There are several plugging directly into the cluster and a couple of long ones that go to the Electronic Display Unit. They are all so that you can't interchange them, they either won't reach to the wrong hole or they have pins to prevent putting them in the wrong place. On turbo's, disconnect the vacuum line going to the turbo gauge.​

Now just remove the cluster and replace the bulbs. Use the same wattage bulbs. Some come out of the holders and some have the holder made to the bulb. The smaller ones come with the holders and the larger ones are replaceable.​

There is one special bulb for the charging system battery light. If an exact replacement can't be found for it, leave it be. It is of a different crucial wattage for the charging system to function properly. The bulbs for the Electronic Display Unit are in the very bottom of the cluster. While you have the cluster out, clean the connections and I suggest replacing all the bulbs while you are there.​

Also while it is out, if you have fuel gauge problems, check the solder joints to the gauge, I have found many cracked. Resoldering them fixes the gauge. They commonly mess up with bumps or heat. You will have to separate the cluster sections to inspect the fuel gauge.​

Installation is the reverse of removal, just be careful to get the clip at the rear of the dash top in place, the cable in the clips if equipped and the feet for the cluster. Make sure you reconnect the turbo hose on turbo's. Check all the bulbs before replacing the dash top after reinstalling the cluster. You should be able to do this in about an hour or less.​

NOTE: On late models, 1994-1998 9000, after making sure you have disconnected the battery, you need to pry off the ABS deco, gently prying towards the rear, to expose the final screw holding the dash on the
passengers side.​




Schematic for Instrument and Control Lighting:




And component list:

COMPONENT ID

10
Lights switch on dashboard between steering wheel and driver’s door.
16
Rheostat, lighting for instruments and controls, on dashboard between the steering wheel and driver’s door.
18
Lighting, main instrument display panel on dashboard.
22a
Fuse board behind the access panel in the glove box.
25
Switch, hazard flashers, beside center air vent in dashboard.
47
Main instrument display panel, dashboard.
48
Cigarette lighter on the center console beside the ashtray.
49
Clock in the center of the dashboard.
88
Switch, extra fog lights, on dashboard between steering wheel and driver’s door.
91
Lighting, selector lever indicator, beside the selector lever in the center console.
116
Switch, electrically heated rear window, on control panel for heating and ventilation.
143
Switch, recirculation, on dashboard between the center console and steering wheel.
148
Ashtray lighting, cigarette lighter on center console.
154
Lighting, control panel for heating and ventilation on centre console.
161
Switch, rear fog lights, on dashboard between the steering wheel and driver’s door.
169
A/C switch, on the dashboard between the centre console and steering wheel.
174
Relay, daylight driving lights, in main fuse box behind the glove box.
210
EDU trip computer in the main instrument display panel.
216
ACC control module in the middle of the dashboard.
241
SCC trip computer in the centre of the dashboard.
252D
Rheostat, driver’s seat heating pad, on dashboard between the steering wheel and centre console.
252P
Rheostat, passenger’s seat heating pad, on dashboard between the steering wheel and centre console.
267 (H10-3)
Radio connector (10-pin) on the centre console beside the place reserved for the radio.
282
Switch, headlamp beam adjustment, on dashboard between the steering wheel and driver’s door.
386
Switch unit, electric window lifts and electrically operated sunroof, on the centre console between the seats.
449
Switch, TCS ON/OFF, on the dashboard.



1-Pin Connector


H1-4
Under the centre console beside the selector lever.



2-Pin Connector


H-17
Adjacent to the heater control panel.



Grounding Points


G2
Grounding point on the battery tray.
G6
Grounding point, negative distribution terminal, in the main fuse box (22B) behind the glove box.
G8
Grounding point, dashboard, by the left-hand front loudspeaker socket.
G14
Grounding point, left-hand seat member, under the left-hand front seat.
G24
Grounding point, right-hand seat member, under the right-hand front seat.

DESCRIPTION OF OPERATION
Rheostat 16, which regulates the lighting for instruments and controls, incorporates an electronic unit.

The rheostat is supplied with current via fuse 29. Rheostat 16 is used for steplessly adjusting the brightness of the lighting of connected components by means of a PWM signal. The brightness of the rheostat lighting is also adjusted at the same time.

Current from pin 2 is supplied to the following components:

10
Lights switch
25
Switch, hazard flashers
116
Switch, electrically heated rear window
143
Switch, recirculation
148
Ashtray illumination, front
154
Lighting, heater controls
161
Switch, rear fog lights
169
A/C switch
216
Climate control unit
252D
Rheostat, heating pad, driver’s seat
252P
Rheostat, heating pad, passenger’s seat

Current is supplied from pin 3 of the rheostat to the following components:
91
Selector lever lamp
386
Switches, electric window lifts, electrically operated sunroof

Current is supplied from pin 5 of the rheostat to the following components:
18
Lighting, main instrument display panel 47
49/241
Clock or SCC trip computer
210
EDU trip computer
267
Radio, dial illumination
282
Headlamp beam adjustment switch

Current is supplied from pin 9 of the rheostat to the following components:
88/88a
Switch, extra fog lights
449
Switch, TCS ON/OFF

FAULT DIAGNOSIS HINTS


1. Check that fuse 29 is intact and supplied with current.
2. Check that current is supplied to pin 7 of the rheostat.
3. Check that pins 2, 3, 5 and 9 of the rheostat are supplied with current.
4. Check that pin 1 of the rheostat is connected to ground
5. Check that the connections and grounding of each component are satisfactory
 

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Dang, I was hoping it'll be something simple like a bad connection. :p

I'll add changing the bulb onto my list of things I gotta fix.
 

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I think - that they're talking about just the LED intensity of the computer (EDU) info display that is controlled by the SCC - not the cluster illumination (i.e backlighting).

The data from the computer is displayed in the lowest part of the instrument cluster - right in the middle - and is displayed by the use of LED's. It shows outside air temp, system voltage, mpg, etc. The intensity of that lighting is controlled by the previously mentioned light sensor on the SCC

If you are having problems with the backlighting, rather than the LED display for the EDU, that is controlled by the interior lighting rheostat on the dashboard.

There are 7 lamps in the cluster that repined to that rheostat - 4 for general lighting and 3 for the EDU display:




As shown in the above image the EDU backlighting consists of 3 lamps. Here is the procedure for changing them:



Special Thanks to Tom Townsend for this information!​

SAAB 9000 EDU BULB REPLACEMENT

First you'll need a 20 torx driver, a 10 torx driver, or possibly a Phillips screwdriver, depending on the year of the car, a 8 mm socket or wrench and a 25 torx driver.​

Pop off the trim pieces on each A-pillar, by the windshield. They are held by three clips that just pop out when you pull back on the panel. Then remove the three screws holding the speaker grills on each side. Be careful if they have LEDs or solar sensor installed in them. If you go back down the LEDs length, you can unplug them at a connector. Make sure you position the wiring so you won't forget it on reassembly or lose it down in the dash. Remove the rubbery speaker insulation.​




Now remove the two screws on each side as well as the 8 mm bolt holding the dash top down. On the side above the glove box, open the glove box and remove the rubber plug along its upper side. There is a screw behind that plug. Remove it. On newer 9000's there is one more screw about 2/3 of the way across the instrument cluster going upward into the dashpot. Find and remove it if the dash top seems to still be held there. After the screws are out, raise the front of the dash top and pull it toward you. Some have a cable that needs to be installed in a clip, all have a clip at the rear center that must be pulled in and out of. Carefully remove the dashpot from the car, it has sharp edges that may cut seats, dash etc. Newer cars have the solar sensor in the center of the dash, reach in and disconnect its wiring.​

There are two screws at the upper corners of the instrument cluster. They come in from the back. The bottom of the cluster is held by two feet with rubber boots on them. Picking up the cluster often causes these feet to fall off. I find them and use a bit of glue to hold them to the cluster. If they aren't reinstalled, the cluster will fit loosely and rattle, vibrate. If the feet are lost, you can slit a piece of vacuum line and use it in their place or PlayDoh or dum will work too.​

With the key off, carefully unplug the electrical connectors. There are several plugging directly into the cluster and a couple of long ones that go to the Electronic Display Unit. They are all so that you can't interchange them, they either won't reach to the wrong hole or they have pins to prevent putting them in the wrong place. On turbo's, disconnect the vacuum line going to the turbo gauge.​

Now just remove the cluster and replace the bulbs. Use the same wattage bulbs. Some come out of the holders and some have the holder made to the bulb. The smaller ones come with the holders and the larger ones are replaceable.​

There is one special bulb for the charging system battery light. If an exact replacement can't be found for it, leave it be. It is of a different crucial wattage for the charging system to function properly. The bulbs for the Electronic Display Unit are in the very bottom of the cluster. While you have the cluster out, clean the connections and I suggest replacing all the bulbs while you are there.​

Also while it is out, if you have fuel gauge problems, check the solder joints to the gauge, I have found many cracked. Resoldering them fixes the gauge. They commonly mess up with bumps or heat. You will have to separate the cluster sections to inspect the fuel gauge.​

Installation is the reverse of removal, just be careful to get the clip at the rear of the dash top in place, the cable in the clips if equipped and the feet for the cluster. Make sure you reconnect the turbo hose on turbo's. Check all the bulbs before replacing the dash top after reinstalling the cluster. You should be able to do this in about an hour or less.​

NOTE: On late models, 1994-1998 9000, after making sure you have disconnected the battery, you need to pry off the ABS deco, gently prying towards the rear, to expose the final screw holding the dash on the
passengers side.​




Schematic for Instrument and Control Lighting:




And component list:

COMPONENT ID

10
Lights switch on dashboard between steering wheel and driver’s door.
16
Rheostat, lighting for instruments and controls, on dashboard between the steering wheel and driver’s door.
18
Lighting, main instrument display panel on dashboard.
22a
Fuse board behind the access panel in the glove box.
25
Switch, hazard flashers, beside center air vent in dashboard.
47
Main instrument display panel, dashboard.
48
Cigarette lighter on the center console beside the ashtray.
49
Clock in the center of the dashboard.
88
Switch, extra fog lights, on dashboard between steering wheel and driver’s door.
91
Lighting, selector lever indicator, beside the selector lever in the center console.
116
Switch, electrically heated rear window, on control panel for heating and ventilation.
143
Switch, recirculation, on dashboard between the center console and steering wheel.
148
Ashtray lighting, cigarette lighter on center console.
154
Lighting, control panel for heating and ventilation on centre console.
161
Switch, rear fog lights, on dashboard between the steering wheel and driver’s door.
169
A/C switch, on the dashboard between the centre console and steering wheel.
174
Relay, daylight driving lights, in main fuse box behind the glove box.
210
EDU trip computer in the main instrument display panel.
216
ACC control module in the middle of the dashboard.
241
SCC trip computer in the centre of the dashboard.
252D
Rheostat, driver’s seat heating pad, on dashboard between the steering wheel and centre console.
252P
Rheostat, passenger’s seat heating pad, on dashboard between the steering wheel and centre console.
267 (H10-3)
Radio connector (10-pin) on the centre console beside the place reserved for the radio.
282
Switch, headlamp beam adjustment, on dashboard between the steering wheel and driver’s door.
386
Switch unit, electric window lifts and electrically operated sunroof, on the centre console between the seats.
449
Switch, TCS ON/OFF, on the dashboard.



1-Pin Connector


H1-4
Under the centre console beside the selector lever.



2-Pin Connector


H-17
Adjacent to the heater control panel.



Grounding Points


G2
Grounding point on the battery tray.
G6
Grounding point, negative distribution terminal, in the main fuse box (22B) behind the glove box.
G8
Grounding point, dashboard, by the left-hand front loudspeaker socket.
G14
Grounding point, left-hand seat member, under the left-hand front seat.
G24
Grounding point, right-hand seat member, under the right-hand front seat.

DESCRIPTION OF OPERATION
Rheostat 16, which regulates the lighting for instruments and controls, incorporates an electronic unit.

The rheostat is supplied with current via fuse 29. Rheostat 16 is used for steplessly adjusting the brightness of the lighting of connected components by means of a PWM signal. The brightness of the rheostat lighting is also adjusted at the same time.

Current from pin 2 is supplied to the following components:

10
Lights switch
25
Switch, hazard flashers
116
Switch, electrically heated rear window
143
Switch, recirculation
148
Ashtray illumination, front
154
Lighting, heater controls
161
Switch, rear fog lights
169
A/C switch
216
Climate control unit
252D
Rheostat, heating pad, driver’s seat
252P
Rheostat, heating pad, passenger’s seat

Current is supplied from pin 3 of the rheostat to the following components:
91
Selector lever lamp
386
Switches, electric window lifts, electrically operated sunroof

Current is supplied from pin 5 of the rheostat to the following components:
18
Lighting, main instrument display panel 47
49/241
Clock or SCC trip computer
210
EDU trip computer
267
Radio, dial illumination
282
Headlamp beam adjustment switch

Current is supplied from pin 9 of the rheostat to the following components:
88/88a
Switch, extra fog lights
449
Switch, TCS ON/OFF

FAULT DIAGNOSIS HINTS


1. Check that fuse 29 is intact and supplied with current.
2. Check that current is supplied to pin 7 of the rheostat.
3. Check that pins 2, 3, 5 and 9 of the rheostat are supplied with current.
4. Check that pin 1 of the rheostat is connected to ground
5. Check that the connections and grounding of each component are satisfactory
I thought it would be easy for me to understand. But after reading the some of these feeling like i am gonna hypnotize. It isn't so easy how i thought and actually it isn't be.
 
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